Light magnesium-based composite material brake rotor

Abstract

A brake rotor for a motor vehicle having a composite structure may include an annular body defining opposing friction surfaces of the brake rotor. The annular body may include a core made of a lightweight magnesium-based alloy; a thermal barrier layer made of a thermal insulation material, the thermal barrier layer disposed on the core; and a wear resistant layer made of an Al-Fe-Si-Zr alloy of aluminum (Al) + iron (Fe) + silicon (Si) + zirconium (Zr), the wear resistant layer disposed on the core over the thermal barrier layer. The wear layer may define a first friction surface of the opposing friction surfaces of the annular body.

Description

Background Art

[0001] The present disclosure relates generally to brake rotors, and more particularly, to composite brake rotors made from lightweight magnesium-based alloys.

[0002] A motor vehicle disc brake assembly includes a disc or rotor with a pair of annular friction surfaces on opposing sides. The rotor can be mounted on a rotatable shaft of the vehicle, which can be coupled to the vehicle's wheels. During braking, the rotor's outer periphery is clamped between a pair of opposing brake pads, which engage the rotor's friction surfaces and slow or stop the rotor and wheel's rotation. Motor vehicle brake rotors are typically made of cast iron, which can withstand the high friction and high temperatures generated during braking. Summary of the Invention

[0003] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0004] It is recognized herein that it may be desirable to manufacture the brake rotors for motor vehicles summarized above from relatively lightweight magnesium alloys, for example, to reduce the weight of the vehicle. It may be desirable to develop a magnesium-based alloy brake rotor for motor vehicles that exhibits wear resistance and thermal stability at least as high as cast iron.

[0005] To this end, the present disclosure relates to a brake rotor having a composite structure for a motor vehicle. The brake rotor includes an annular body defining opposing friction surfaces. The annular body includes a core, a thermal barrier layer, and a wear-resistant layer. The core is made of a magnesium-based alloy (e.g., an alloy of magnesium (Mg) + aluminum (Al) + zinc (Zn) (i.e., Mg-Al-Zn)) and includes at least one annular disk having an annular surface. The thermal barrier layer is made of a thermally insulating material and is disposed on the annular surface of the core. The wear-resistant layer is disposed on the annular surface of the core above the thermal barrier layer. The wear-resistant layer defines a first friction surface among the opposing friction surfaces of the annular body and can be made of an alloy of aluminum (Al) + iron (Fe) + silicon (Si) + zirconium (Zr) (i.e., Al-Fe-Si-Zr).

[0006] In some examples, the magnesium-based alloy may be a Mg-Al-Zn alloy, such as AZ31, AZ61, or AZ91. The magnesium-based alloy may contain, by mass, approximately 93% Mg, approximately 6% Al, and approximately 1% Zn. In terms of weight percentage, the magnesium-based alloy may contain approximately 3.8-5.0% aluminum, approximately 0.8-1.5% zinc, approximately 0.3-0.7% manganese, with the balance being magnesium. Alternatively, the magnesium-based alloy may include a composite material containing a Mg-Al-Zn alloy and boron nitride (BN) and / or boron carbide (B2C).

[0007] The core material may have a viscosity greater than or equal to about 1.7 g / cm3 to less than or equal to about 1.9 g / cm 3 density, a thermal conductivity of about 90 W / mK to about 100 W / mK; and a thickness of greater than or equal to about 9 mm to less than or equal to about 36 mm.

[0008] In some examples, the thermally insulating material can include a high entropy alloy, a high entropy ceramic, or a combination thereof.The thermally insulating material can have a thermal conductivity greater than or equal to about 0.4 Watts per meter-Kelvin to less than or equal to 2 W / mK.

[0009] In some examples, the wear resistant layer may include an Al-Fe-Si-Zr alloy. The Al-Fe-Si-Zr alloy may include Al 50 Fe 42 The Si6Zr2.Al-Fe-Si-Zr alloy may have a density of greater than or equal to about 4,800 kg / m3 to less than or equal to about 5,200 kg / m3.

[0010] In other examples, the Al-Fe-Si-Zr wear-resistant alloy may optionally include a grain refiner in an amount greater than or equal to about 0.05% to less than or equal to about 1% by mass of the Al-Fe-Si-Zr alloy. The grain refiner may include at least one of chromium (III) boride and tantalum boride.

[0011] In some examples, the thermal barrier layer can have a thickness of greater than or equal to about 0.05 mm to less than or equal to about 4 mm. The wear resistant layer can have a thickness of greater than or equal to about 1 mm to less than or equal to about 4 mm.

[0012] In some examples, the thermal barrier layer can be perforated and can include a plurality of through-holes extending therethrough in an axial direction. The wear-resistant layer can include a plurality of anchors extending from an outer surface of the thermal barrier layer toward the core into the plurality of through-holes. The plurality of anchors can extend from the outer surface of the thermal barrier layer into the plurality of through-holes to the annular surface of the core. In this case, the Al—Fe—Si—Zr alloy of the wear-resistant layer can be metallurgically bonded to the magnesium-based alloy of the core via the plurality of anchors.

[0013] In some examples, the core may include a pair of first and second annular disks spaced apart from each other in the axial direction by a plurality of ribs.

[0014] The present disclosure relates to another brake rotor for a motor vehicle, comprising an annular body defining opposing first and second friction surfaces of the brake rotor. In some examples, the annular body includes a core, first and second thermal barrier layers, and first and second wear-resistant layers. The core is made of a magnesium-based alloy and includes a pair of first and second annular discs spaced apart from each other in the axial direction by a plurality of ribs, wherein each of the first and second annular discs has an annular surface. The first and second thermal barrier layers are made of a thermally insulating material and are disposed on the annular surfaces of the first and second annular discs of the core, respectively. The first and second wear-resistant layers may be made of an Al-Fe-Si-Zr alloy and are disposed on the annular surfaces of the first and second annular discs, respectively, above the first and second thermal barrier layers. The first and second wear-resistant layers define the opposing first and second friction surfaces of the annular body, respectively.

[0015] A method for manufacturing a brake rotor for a motor vehicle is disclosed. In some examples, a magnesium-based alloy is cast into the shape of a rotor core, which includes at least one annular disk having an annular surface. A thermal insulation material is deposited directly on the annular surface of the rotor core to form a thermal barrier layer. An Al-Fe-Si-Zr alloy may be deposited on the annular surface of the rotor core above the thermal barrier layer to form a wear-resistant layer.

[0016] In some examples, a thermal insulation material and an Al-Fe-Si-Zr alloy can be deposited on the annular surface of the rotor core using a directed energy deposition process. The thermal insulation material can be deposited on the annular surface of the rotor core such that the thermal barrier layer is perforated and includes a plurality of through-holes extending therethrough in an axial direction. During the deposition of the Al-Fe-Si-Zr alloy on the annular surface of the rotor core, the Al-Fe-Si-Zr alloy can flow into and through the through-holes in the thermal barrier layer and form a plurality of anchors that metallurgically bond the Al-Fe-Si-Zr alloy of the wear-resistant layer to the magnesium-based alloy of the core.

[0017] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0019] Figure 1 is a perspective view of a brake rotor for a disc brake assembly for a motor vehicle, wherein the brake rotor includes a hub and an annular body.

[0020] Figure 2 It is along Figure 1 The line 2-2 intercepts Figure 1 Schematic cross-sectional view of an annular body, wherein the annular body includes a core, first and second thermal barrier layers disposed on the core, and first and second wear resistant layers disposed on the core over the first and second thermal barrier layers.

[0021] Figure 3 is a schematic cross-sectional view of a thermal barrier layer having a perforated structure and including a plurality of through-holes extending therethrough.

[0022] Figure 4 is a schematic cross-sectional view of an annular body of a brake rotor, wherein the annular body includes a core, a perforated first thermal barrier layer and a perforated second thermal barrier layer disposed on the core, and first and second wear resistant layers disposed on the core over the first and second thermal barrier layers, and wherein the first and second wear resistant layers each include a plurality of anchors extending from outer surfaces of the first and second thermal barrier layers, respectively, into a plurality of through-holes in the perforated first and second thermal barrier layers to the core.

[0023] Figure 5 is used in Figure 2 and Figure 4 Schematic cross-sectional view of an apparatus for depositing first and second thermal barrier layers and first and second wear resistant layers on a core of an annular body.

[0024] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0025] Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Many specific details, such as examples of specific compositions, components, devices, and methods, are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed and that the example embodiments may be embodied in many different forms, and neither should be construed as limiting the scope of the present disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0026] As used herein, the term "metal" may refer to an alloy of pure elemental metal or elemental metal with one or more other metals or non-metallic elements (referred to as "alloying" elements). Alloying elements may be selected to impart certain desired properties to the alloy that are not exhibited by the base metal elements. Alloys as described herein may be represented by a series of chemical symbols for base elements (e.g., Mg) and their primary alloying elements (e.g., Al and Zn), wherein the alloying elements are arranged in descending order of mass percent (or alphabetically if the percentages are similar or equal), such as Mg-Al-Zn alloys. Sometimes, for one or more alloying elements, a numeral may be present before the chemical symbol. In this case, unless otherwise indicated, the numeral before the chemical symbol of the alloying element represents the average mass percent of the element in the alloy composition.

[0027] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0028] A brake rotor for a motor vehicle disclosed herein includes a composite structure that allows the brake rotor to be relatively lightweight while also exhibiting excellent wear resistance and thermal stability. The brake rotor has an annular body with first and second friction surfaces disposed on opposite sides thereof. The annular body includes a core made of a relatively lightweight magnesium-based alloy and first and second wear-resistant layers disposed on the first and second friction surfaces of the annular body, respectively. The first and second wear-resistant layers can be made of an Al-Fe-Si-Zr alloy, which is relatively hard and dense compared to the magnesium-based alloy of the core. First and second thermal barrier layers are sandwiched between the first friction surface and the first wear-resistant layer, and between the second friction surface and the second wear-resistant layer, respectively. The first and second thermal barrier layers thermally insulate the magnesium-based alloy of the core from the relatively high temperatures generated in the first and second wear-resistant layers during braking. For example, the first and second thermal barrier layers disposed on opposite sides of the magnesium-based alloy of the core can help maintain the core at a temperature of less than approximately 350 degrees Celsius (°C), even when the temperature of the first and second wear-resistant layers exceeds approximately 550°C. The magnesium-based alloy may include a Mg-Al-Zn alloy.

[0029] Figure 1A brake rotor 10 is depicted for a disc brake assembly for a motor vehicle (not shown). The brake rotor 10 includes a hub 12, an annular body 14, and a central opening 16 defining an axis of rotation 18 of the brake rotor 10. The hub 12 can be configured to mount the brake rotor 10 to a rotatable axle of the motor vehicle. The annular body 14 extends radially from the central opening 16 and defines an outer periphery 20 of the brake rotor 10 and first and second friction surfaces 22, 24 disposed on opposite sides of the brake rotor 10. The first and second friction surfaces 22, 24 are configured to engage brake pads (not shown) disposed on opposite sides of the brake rotor 10 to generate friction forces that resist rotation of the brake rotor 10 during braking.

[0030] As will be appreciated by those skilled in the art, the presently disclosed brake rotor 10 may take on other configurations. For example, in some aspects, the hub 12 may be omitted, and the brake rotor 10 may be coupled to a rotatable shaft of a motor vehicle by other means.

[0031] Now refer to Figure 2 , the annular body 14 exhibits a composite structure including a core 26, first and second thermal barrier layers 28, and first and second wear resistant layers 30. The core 26 includes at least one annular disk 32 or 34 defining a pair of annular surfaces 38 disposed on opposite sides of the brake rotor 10 and facing away from the core 26. Figure 2 The core 26 depicted in FIG includes a pair of first and second annular disks 32, 34 disposed on opposite sides of the brake rotor 10 and spaced apart from one another in the axial direction 18 by a plurality of ribs 36. Each of the first and second annular disks 32, 34 has an annular surface 38 facing away from the core 26. The core 26 may have a thickness of greater than or equal to approximately 9 mm to less than or equal to approximately 36 mm measured between the opposing annular surfaces 38. The core 26 may include a unitary, one-piece construction.

[0032] The core 26 may be made of a magnesium-based alloy, for example, comprising 93% Mg, 6% Al, and 1% Zn by mass (i.e., AZ61 alloy). Alternatively, alloys AZ31 or AZ91 may be used, wherein alloy AZ31 comprises 97% Mg, 2.5-3.5% Al, and 0.5-1.5% Zn; and alloy AZ91 comprises 90% Mg, 9% Al, and 1% Zn.

[0033] The first and second thermal barrier layers 28, 28 are respectively disposed on opposing annular surfaces 38 of the core 26 and are configured to inhibit heat transfer from the first and second friction surfaces 22, 24 of the brake rotor 10 to the core 26 during braking. In some aspects, the first and second thermal barrier layers 28 may be deposited directly on the opposing annular surfaces 38 of the core 26. The thermal barrier layers 28 may help maintain the core 26 at a temperature below approximately 350°C, even when the temperature of the first and second wear layers 30 is greater than approximately 550°C. Each of the first and second thermal barrier layers 28 may have a thickness, measured from the annular surface 38 of the core 26, of greater than or equal to approximately 0.05 mm to less than or equal to approximately 2 m, or less than or equal to approximately 4 m. The thermal barrier layers 28 may be substantially coextensive with the annular surface 38 of the core 26.

[0034] The first and second thermal barrier layers 28 may be made of a thermally insulating material having a relatively lower thermal conductivity than the thermal conductivity of the core 26 and the first and second wear-resistant layers 30. For example, the thermal conductivity of the thermally insulating material may be about 5-20% of the thermal conductivity of the wear-resistant layer 30. The thermal conductivity of the thermally insulating material may be greater than or equal to about 0.4 W / mK or about 0.5 W / mK to less than or equal to 0.7 W / mK or less than or equal to about 2 W / mK. The thermally insulating material may have a thermal conductivity of about 1.46 g / cm 3 density and a specific heat of about 1.5 J / gK.

[0035] The insulating material of the thermal barrier layer 28 may include a high entropy alloy, a high entropy ceramic, or a combination thereof. A high entropy alloy or ceramic material is an inorganic alloy or ceramic material that (a) includes at least four elements, each element having an atomic concentration in the alloy or ceramic of greater than or equal to about 5% to less than or equal to about 35%, and / or (b) exists in the form of a solid solution without an intermetallic phase. Examples of high entropy alloys include bismuth (Bi) and tellurium (Te) (i.e., Bi-Te) based materials, and bismuth (Bi), antimony (Sb), tellurium (Te), and selenium (Se) (i.e., Bi-Sb-Te-Se) based materials, such as BiSbTe. 1.5 Se 1.5 and / or (BiSbTe 1.5 Se 1.5 )1-xAgx, where x is about 0.9 atomic percent and Ag is silver. Examples of high entropy ceramics include zirconate (Zr x O y -z ) materials and materials based on rare earth metal zirconates (R2Zr2O7), where R can be La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3 and / or Y2O3; and where Zr = zirconium, La = lanthanum, Nd = neodymium, Sm = samarium, Eu = europium, Gd = gadolinium, Y = yttrium, and O = oxygen.

[0036] The first and second wear-resistant layers 30, 30 are disposed on the first and second thermal barrier layers 28, 28, respectively, and define the first and second friction surfaces 22, 24, respectively, of the brake rotor 10. In some aspects, the first and second wear-resistant layers 30 can be deposited directly on the first and second thermal barrier layers 28, respectively. The first and second wear-resistant layers 30 are configured to provide high wear resistance and excellent thermal stability to the first and second friction surfaces 22, 24 of the brake rotor 10. For example, the first and second wear-resistant layers 30 can be formulated to exhibit excellent mechanical stability at high temperatures, such as temperatures up to approximately 1,300°C. Each of the first and second wear-resistant layers 30 can have a thickness, measured from the surface of the adjacent thermal barrier layer 28, of greater than or equal to approximately 1 mm to less than or equal to approximately 2 mm, or less than or equal to approximately 4 mm. The wear-resistant layers 30 can be substantially coextensive with the thermal barrier layer 28 and the annular surface 38 of the core 26.

[0037] The first wear resistant layer and the second wear resistant layer 30 can be made of an aluminum alloy that contains the alloying elements iron (Fe), silicon (Si), and zirconium (Zr) in addition to aluminum (Al), and can therefore be referred to as an Al-Fe-Si-Zr alloy. The amounts of iron, silicon, and zirconium in the aluminum alloy are selected to provide an Al-Fe-Si-Zr alloy having high strength, excellent wear resistance, oxidation resistance, and corrosion resistance. In the Al-Fe-Si-Zr alloy, the aluminum, iron, silicon, and zirconium can be present in the form of intermetallic compound particles containing AlFeSiZr. The Al-Fe-Si-Zr alloy can include Al 50 Fe 42 Si6Zr2.

[0038] In some aspects, the Al-Fe-Si-Zr alloy may include a grain refiner. Examples of grain refiners include boride compounds, such as chromium (III) boride (CrB) and / or tantalum boride (e.g., TaB and / or TaB2). In embodiments where the grain refiner comprises chromium (III) boride and tantalum boride, the mass ratio of chromium (III) boride to tantalum boride in the Al-Fe-Si-Zr alloy may be approximately 1:1. The grain refiner may be present in the Al-Fe-Si-Zr alloy in an amount of greater than or equal to about 0.05 mass % to less than or equal to about 1 mass % of the Al-Fe-Si-Zr alloy.

[0039] The Al-Fe-Si-Zr alloy can exhibit a relatively high density compared to the density of magnesium-based alloys and / or thermal insulation materials. For example, the density of the Al-Fe-Si-Zr alloy is greater than or equal to about 4.8 g / cm 3 to less than or equal to about 5.2 g / cm 3In one example, an Al-Fe-Si-Zr alloy may have a density of about 4.99 g / cm 3 The Al—Fe—Si—Zr alloy may have a thermal conductivity of greater than or equal to about 11 W / mK to less than or equal to about 13 W / mK and a specific heat of greater than or equal to about 0.61 J / kK to less than or equal to about 0.67 J / gK.

[0040] Nevertheless, additional elements not intentionally introduced into the compositions of the Mg-Al-Zn alloys and / or Al-Fe-Si-Zr alloys disclosed herein may be inherently present in the alloys in relatively small amounts, for example, in individual and / or cumulative amounts, by mass, less than or equal to about 0.1%, alternatively less than or equal to about 0.05%, or alternatively less than or equal to about 0.01%. Such elements may be present, for example, as impurities in the raw materials or scrap used to prepare the alloys. In embodiments where an alloy is referred to as comprising one or more alloying elements (e.g., Si) and aluminum or iron as a balance, the term "as a balance" does not exclude the presence of additional elements not intentionally introduced into the alloy composition but still inherently present in the alloy in relatively small amounts, for example, as impurities.

[0041] Now refer to Figure 3 In some aspects, the first and second thermal barrier layers 28 can be perforated. The thermal barrier layer 28 can include a plurality of through holes 40 extending in an axial direction through the thermal barrier layer 28. In various aspects, the through holes 40 can extend completely through the thermal barrier layer 28 to the core 26. In this case, as Figure 4 As shown, the first wear resistant layer 30 and the second wear resistant layer 30 can each include a plurality of anchors 42 that extend from an outer surface 44 of the first thermal barrier layer 28 and the second thermal barrier layer 28, respectively, into a plurality of through-holes 40 in the thermal barrier layer 28 to the annular surface 38 of the core 26. In this case, the Al-Fe-Si-Zr alloy of the wear resistant layer 30 can be metallurgically bonded to the magnesium-based alloy of the core 26 via the plurality of anchors 42.

[0042] An example method of manufacturing a brake rotor 10 for a motor vehicle may include one or more of the following steps. In a first step, a magnesium-based alloy may be cast into the shape of a core 26. In a second step, a thermal insulation material may be deposited directly onto the annular surface 38 of the core 26 to form the first and second thermal barrier layers 28. In some aspects, the thermal insulation material may be selectively deposited onto the annular surface 38 of the core 26 in a predetermined pattern, for example, such that the resulting first and second thermal barrier layers 28 are perforated and include a plurality of through-holes 40. In a third step, a wear-resistant alloy (e.g., Al—Fe—Si—Zr) may be deposited onto the annular surface of the core 26 over the first and second thermal barrier layers 28 to form the first and second wear-resistant layers 30. In aspects where the first and second thermal barrier layers 28 are perforated, the wear-resistant alloy may flow into the plurality of through-holes 40 and form a plurality of anchors 42 that may metallurgically bond to the annular surface 38 of the core 26.

[0043] Now refer to Figure 5 In some aspects, the thermal insulation material and the wear-resistant alloy can be separately and sequentially deposited on the annular surface 38 of the core 26 using a directed energy deposition process. During directed energy deposition, a feedstock material 146 is deposited on the annular surface 38 of the core 26 via a nozzle 148 and simultaneously melted by applying a focused energy source 150 thereto. The nozzle 148 and focused energy source 150 are advanced along the annular surface 38 of the core 26 in a predetermined pattern, leaving behind a layer of solidified feedstock material 152. The focused energy source can be a plasma arc, an electron beam, or a laser, or a combination thereof. A shielding gas can be applied to an area 154 surrounding the deposition site to prevent or inhibit undesirable side reactions. The feedstock material can be in the form of a wire or powder and can exhibit substantially the same composition as the layer being formed. For example, during the formation of the first and second thermal barrier layers 28, the feedstock material 152 can have a composition substantially the same as that of the thermal insulation material. Similarly, during the formation of the first and second wear-resistant layers 30, the feedstock material 152 can have a composition substantially the same as that of an exemplary Al-Fe-Si-Zr alloy.

[0044] The composite brake rotor 10 may also include a thin adhesion-enhancing interlayer disposed between the core 26 and the thermal barrier layer 28. The interlayer may include a metal or metal alloy selected from the group consisting of Ti (titanium), Cr (chromium), Mo (molybdenum), W (tungsten), Nb (niobium), Ta (tantalum), or combinations thereof. The interlayer may be 0.05-0.5 mm thick and may be deposited by physical vapor deposition (PVD), sputtering, or the like.

[0045] The terms used herein are for the purpose of describing the example embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be intended to include the plural forms, unless the context clearly indicates otherwise. The terms "comprises", "contains", "includes" and "have" are inclusive and therefore specify the presence of the features, elements, compositions, steps, integers, operations and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof. Although the open-ended terms "comprises", "contains", "includes" and "have" should be understood as non-limiting terms for describing and claiming the various embodiments described herein, in some aspects, these terms may alternatively be understood as more restrictive and limiting terms, such as "consisting of" or "consisting essentially of". Thus, for a given embodiment that recites compositions, materials, components, elements, ingredients, features, integers, operations, and / or process steps, the present disclosure also specifically encompasses embodiments consisting of or consisting essentially of such recited compositions, materials, components, elements, ingredients, features, integers, operations, and / or process steps. In the case of "consisting of," alternative embodiments exclude any additional compositions, materials, components, elements, ingredients, features, integers, operations, and / or process steps, while in the case of "consisting essentially of," additional compositions, materials, components, elements, ingredients, features, integers, operations, and / or process steps that materially affect the basic and novel characteristics are excluded from such embodiments, but compositions, materials, components, elements, ingredients, features, integers, operations, and / or process steps that do not materially affect the basic and novel characteristics may be included in the embodiments.

[0046] The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the order discussed or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be employed unless otherwise indicated.

[0047] When a component, element, or layer is referred to as being "on another component or layer," "engaged to," "connected to," or "coupled to" another component or layer, it may be directly on, directly engaged, connected, or coupled to the other component, element, or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes a combination of one or more of the associated listed items.

[0048] Although the terms first, second, third etc. can be used herein to describe various steps, elements, components, regions, layers and / or parts, unless otherwise indicated, these steps, elements, components, regions, layers and / or parts should not be restricted by these terms. These terms can be used to distinguish a step, element, component, region, layer or part from another step, element, component, region, layer or part. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply sequence or order when used in this article. Therefore, without departing from the teaching of example embodiments, the first step, element, component, region, layer or part discussed below can be referred to as the second step, element, component, region, layer or part.

[0049] For ease of description, spatial or temporal relative terms, such as "before," "after," "inside," "outside," "below," "beneath," "lower," "above," and the like, may be used herein to describe the relationship of one element or feature to another element or features, as shown in the figures. Spatially or temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.

[0050] Throughout this disclosure, numerical values represent approximate measurements or limits to ranges and encompass minor deviations from given values and embodiments, with values approximately as well as those having the values exactly as mentioned. Except for the working examples provided at the end of the detailed description, all numerical values of parameters (e.g., quantities or conditions) in this specification (including the appended claims) should be understood to be modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. "About" means that the numerical value allows some slight imprecision (to some extent close to the accuracy of the value, approximately or reasonably close to the value, close). If the imprecision provided by "about" is not otherwise understood in this art with this ordinary meaning, then "about" as used herein at least represents the variation that may be caused by the common methods of measuring and using these parameters. For example, "about" can include less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some aspects, optionally less than or equal to 0.1%.

[0051] Furthermore, disclosure of ranges includes disclosure of all values within the entire range and further divided ranges, including endpoints and sub-ranges given for the ranges.

[0052] As used herein, the terms "composition" and "material" are used interchangeably to broadly refer to a substance that contains at least some chemical constituents, elements, or compounds, but which may also contain additional elements, compounds, or substances, including trace amounts of impurities, unless otherwise indicated. A composition or material that is "based on X" broadly refers to a composition or material in which "X" is the single largest constituent of the composition or material on a weight percent (%) basis. This can include compositions or materials that have greater than 50% X by weight, as well as those that have less than 50% X by weight, as long as X is the single largest constituent of the composition or material based on its total weight.

[0053] The foregoing description of the embodiments has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular embodiment are generally not limited to the embodiments, but are interchangeable where applicable and can be used in selected embodiments, even if not specifically shown or described. They may also vary in many ways. Such variations should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. A brake rotor for a motor vehicle, the brake rotor comprising: an annular body defining a first friction surface, the annular body comprising: a core comprising a magnesium-based alloy and including at least one annular disk having an annular surface; a thermal barrier layer comprising a thermally insulating material and disposed on an annular surface of the core; and a wear-resistant Al-Fe-Si-Zr alloy layer comprising aluminum (Al) + iron (Fe) + silicon (Si) + zirconium (Zr), the wear-resistant Al-Fe-Si-Zr alloy layer being disposed on the annular surface of the core above the thermal barrier layer; and The wear-resistant layer defines the first friction surface of the annular body. 2 . The brake rotor of claim 1 , wherein the magnesium-based alloy comprises, by mass, approximately 93% magnesium (Mg), approximately 6% aluminum (Al), and approximately 1% zinc (Zn).

3. The brake rotor of claim 1, wherein the magnesium-based alloy comprises approximately 3.8-5.0 wt. % aluminum, approximately 0.8-1.5 wt. % zinc, approximately 0.3-0.7 wt. % manganese, and the balance being magnesium.

4. The brake rotor according to claim 1, wherein: The magnesium-based alloy includes a composite material including a Mg-Al-Zn alloy and boron nitride (BN) and / or boron carbide (B2C).

5. The brake rotor of claim 1 , further comprising an adhesion strengthening interlayer disposed between the core and the thermal barrier layer, the adhesion strengthening interlayer comprising a metal or metal alloy selected from Ti (titanium), Cr (chromium), Mo (molybdenum), W (tungsten), Nb (niobium), or Ta (tantalum), or combinations thereof.

6. The brake rotor of claim 1 , wherein: The core has: About 1.7g / cm 3 to about 1.9g / cm 3 density; a thermal conductivity between about 90 W / mK and about 100 W / mK; a tensile strength between about 260 MPa and about 280 MPa; and A thickness of greater than or equal to about 9 mm to less than or equal to about 36 mm.

7. The brake rotor of claim 1 , wherein: The thermal insulation material includes high entropy alloy, high entropy ceramic or a combination thereof.

8. The brake rotor of claim 1, wherein the thermally insulating material has a thermal conductivity of greater than or equal to approximately 0.4 W / mK to less than or equal to 2 W / mK.

9. The brake rotor of claim 1 , wherein the Al—Fe—Si—Zr alloy comprises Al 50 Fe 42 Si6Zr2.

10. The brake rotor of claim 1 , wherein the Al—Fe—Si—Zr alloy comprises a grain refiner in an amount greater than or equal to about 0.05% to less than or equal to about 1% by mass of the Al—Fe—Si—Zr alloy, and wherein the grain refiner comprises at least one of chromium (III) boride and tantalum boride.

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