Marine combustion chamber of ni cr20 ti al alloy and slm forming method

Abstract

The application provides a marine combustion chamber of NiCr20TiAl alloy and an SLM forming method, and comprises the following steps: an alloy selection step: selecting the powder particle size and composition of the NiCr20TiAl alloy powder; a printing preparation step: loading the NiCr20TiAl alloy powder into a powder supply bin of a 3D printer, leveling and preheating a substrate; a model slicing step: layering a three-dimensional model of the marine combustion chamber after importing a slicing software; a laser forming step: setting the oxygen content, powder layer thickness, laser power, scanning speed and scanning spacing in a forming bin, and the scanning strategy is strip scanning; and a surface treatment step: removing the support until the surface roughness of the marine combustion chamber reaches a preset product standard. The application can shorten the processing cycle, effectively reduce the generation of product defects, and improve the mechanical performance index of the product, so as to meet the application requirements of the marine combustion chamber.

Description

[0001] This application is a divisional application. The original application has the application number "202210440202.2" and the application date "2022.04.25". The invention title is "SLM forming method for marine combustion chamber of NiCr20TiAl alloy". Technical Field

[0002] This invention relates to the field of 3D printing technology, and in particular to a marine combustion chamber made of NiCr20TiAl alloy and a SLM forming method. Background Technology

[0003] In recent years, with the development of the shipbuilding industry at home and abroad, however, marine combustion chambers are irregular and complex structural components. Conventional machining methods are difficult to achieve local twisted structures. In other words, traditional manufacturing methods have great limitations for components with complex internal and external shapes and integrated structures. They also have disadvantages such as long production cycles, low raw material utilization, and low overall assembly accuracy.

[0004] Furthermore, no manufacturers have conducted relevant research on metal 3D printing of NiCr20TiAl alloy.

[0005] Therefore, there is an urgent need for a new additive manufacturing method to replace the traditional forging method for forming marine combustion chambers. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide a marine combustion chamber of NiCr20TiAl alloy and an SLM forming method. Based on the structure of the marine combustion chamber and the new component characteristics of NiCr20TiAl alloy, compared with traditional casting, forging and machining processes, the processing cycle can be shortened, the generation of product defects can be effectively reduced, and the mechanical performance indicators of the product can be improved, thereby meeting the application requirements of marine combustion chambers.

[0007] To solve the above-mentioned technical problems, the present invention provides a marine combustion chamber made of NiCr20TiAl alloy, comprising:

[0008] The combustion chamber body has a first cavity, a second cavity, and a third cavity connected in sequence, with the first cavity and the third cavity both open to the outside;

[0009] The NiCr20TiAl alloy has the following composition by mass percentage: Cr: 18-21%, Al: 1.0-1.8%, Ti: 1.8-2.7%, Co: ≤2.0%, Fe: ≤1.5%, Mn: ≤0.4%, Si: ≤0.8%, P: ≤0.02%, Cu: ≤0.2%, C: 0.04-0.1%, S: ≤0.015%, Ag: ≤0.0005%, Pb: ≤0.002%, B: ≤0.008%, Bi: ≤0.0001%, with the remainder being Ni.

[0010] Preferably, the angle between the axis of the second cavity and the axis of the first cavity is 17.9 degrees, and the angle between the axis of the third cavity and the axis of the first cavity is 65.5 degrees.

[0011] Preferably, the volumes of the first cavity, the second cavity, and the third cavity gradually decrease in size.

[0012] The present invention also provides an SLM molding method for manufacturing the marine combustion chamber, comprising the following steps:

[0013] Alloy selection steps: The particle size of NiCr20TiAl alloy powder is 15-53μm;

[0014] Printing preparation steps: Load NiCr20TiAl alloy powder into the powder supply chamber of the 3D printer, load the substrate to support the 3D printed product into the forming chamber of the 3D printer, level and preheat the substrate. The preheating temperature of the substrate is 80-150℃. Pre-lay a layer of NiCr20TiAl alloy powder with a thickness of 50μm on the substrate.

[0015] Model slicing steps: After importing the 3D model of the marine combustion chamber into the slicing software, perform layer processing, export the corresponding 2D graphics of each layer, and input the preset printing process parameters.

[0016] Laser forming steps: The oxygen content in the forming chamber is ≤1000ppm, the powder layer thickness is 50μm, the laser power is 100-300W, the scanning speed is 800-1200mm / s, the scanning interval is 0.08-1.2mm, the scanning strategy is strip scanning, the width of the strip is 10mm, the starting angle is 57°, and the layer-by-layer rotation angle is 67°;

[0017] Surface treatment steps: Remove the support between the marine combustion chamber and the substrate, and then perform surface sandblasting on the marine combustion chamber until the surface roughness of the marine combustion chamber meets the preset production standard.

[0018] Preferably, the laser forming step further includes: using a laser to selectively melt and form NiCr20TiAl alloy powder according to a preset scanning path; after each printing layer is completed, the substrate is lowered by 50 μm, and another layer of NiCr20TiAl alloy powder is deposited on the substrate, and the selective melting and forming is repeated until all printing layers are completed.

[0019] Preferably, the substrate is made of 304 stainless steel.

[0020] Preferably, the laser forming step further includes: filling the forming chamber of the 3D printer with a protective gas, wherein the forming chamber is located within the forming chamber.

[0021] Preferably, the SLM molding method further includes a product inspection step: observing the cut surface of the printed sample using a metallographic microscope.

[0022] Preferably, the SLM forming method further includes a specimen stretching step: performing tensile tests on the forged specimen and the printed specimen respectively.

[0023] As described above, the marine combustion chamber of NiCr20TiAl alloy and the SLM forming method of the present invention have the following beneficial effects:

[0024] The first, second, and third cavities of the marine combustion chamber are formed within the combustion chamber body, with both the first and third cavities opening outwards. This design creates a complex internal structure and a curved internal flow channel, preventing fuel gas from passing through the combustion chamber rapidly and directly. Instead, it generates turbulence within the combustion chamber body, extending the residence time of the fuel gas and better meeting the application requirements of marine combustion chambers. The mass percentage composition of the aforementioned NiCr20TiAl alloy was developed specifically for the structure of the marine combustion chamber, representing a new NiCr20TiAl alloy that improves the rigidity, strength, and service life of the marine combustion chamber.

[0025] In the SLM forming method, the alloy selection steps are as follows: the particle size of the NiCr20TiAl alloy powder is 15-53 μm, and the mass percentage composition of the NiCr20TiAl alloy is: Cr: 18-21%, Al: 1.0-1.8%, Ti: 1.8-2.7%, Co: ≤2.0%, Fe: ≤1.5%, Mn: ≤0.4%, Si: ≤0.8%, P: ≤0.02%, Cu: ≤0.2%, C: 0.04-0.1%, S: The powder particle size and composition of NiCr20TiAl alloy are selected to account for the complex structure and special application scenarios of marine combustion chambers. This ensures that the formed marine combustion chamber is more compact and homogeneous, which is beneficial for reducing internal defects and improving the mechanical properties of the printed sample in subsequent laser forming and surface treatment steps. Printing preparation steps: Load the NiCr20TiAl alloy powder into the powder supply chamber of the 3D printer. Load the substrate to be used to support the 3D printed product into the forming chamber of the 3D printer. Level and preheat the substrate to a temperature of 80-150℃. Pre-lay a 50μm thick layer of NiCr20TiAl alloy powder on the substrate. Preheating the substrate and pre-laying the powder helps the printed product to be stably formed on the substrate. Model slicing steps: After importing the 3D model of the marine combustion chamber into the slicing software, the model is layered and exported as a 2D graphic corresponding to each layer. Preset printing process parameters are then input. Laser forming steps: The oxygen content in the forming chamber is ≤1000ppm, the powder layer thickness is 50μm, the laser power is 100-300W, the scanning speed is 800-1200mm / s, the scanning spacing is 0.08-1.2mm, the scanning strategy is strip scanning, the strip width is 10mm, the starting angle is 57°, and the layer-by-layer rotation angle is 67°. Selective laser melting 3D printers are used to achieve 3D printing of NiCr20TiAl alloy. According to the above process parameters, selective laser melting directly melts and solidifies the alloy powder under the thermal action of the laser beam to form metal parts with good metallurgical bonding and high precision. This is particularly suitable for manufacturing complex thin-walled precision components that are difficult to achieve with traditional processing techniques. The main characteristics of complex thin-walled precision components are thin walls, complex internal cavities, and curved internal flow channels. Meanwhile, due to the high cooling rate unique to SLM technology, a large-scale non-equilibrium solidification phenomenon occurs during the cooling process, resulting in a fine and dense microstructure, uniform composition, and excellent performance in the molded marine combustion chamber. Surface treatment steps: Remove the support components between the marine combustion chamber and the substrate, and then perform surface sandblasting on the marine combustion chamber until the surface roughness of the marine combustion chamber meets the preset output standard.Therefore, the marine combustion chamber of NiCr20TiAl alloy and the SLM forming method of the present invention, based on the structure of the marine combustion chamber and the new component characteristics of NiCr20TiAl alloy, can shorten the processing cycle, effectively reduce the generation of product defects, and improve the mechanical performance indicators of the product compared with traditional casting, forging and machining processes, thereby meeting the application requirements of marine combustion chambers. Attached Figure Description

[0026] Figure 1 The flowchart shown is a process for manufacturing a marine combustion chamber according to the present invention.

[0027] Figure 2 Shown as a cross-sectional view of a marine combustion chamber;

[0028] Figure 3 The diagram shows a layer-by-layer rotation of the bar scan.

[0029] Figure 4 The image shows the defect distribution of the printed sample as observed using a metallographic microscope.

[0030] Component designation explanation

[0031] 1 Marine combustion chamber

[0032] 11 Combustion Chamber Body

[0033] 12 First cavity

[0034] 13 Second cavity

[0035] 14 Third cavity Detailed Implementation

[0036] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0037] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0038] like Figure 2 As shown, the present invention provides a marine combustion chamber made of NiCr20TiAl alloy, comprising:

[0039] The combustion chamber body 11 has a first cavity 12, a second cavity 13 and a third cavity 14 connected in sequence inside the combustion chamber body 11, and the first cavity 12 and the third cavity 14 are both open to the outside.

[0040] The NiCr20TiAl alloy has the following composition by mass percentage: Cr: 18-21%, Al: 1.0-1.8%, Ti: 1.8-2.7%, Co: ≤2.0%, Fe: ≤1.5%, Mn: ≤0.4%, Si: ≤0.8%, P: ≤0.02%, Cu: ≤0.2%, C: 0.04-0.1%, S: ≤0.015%, Ag: ≤0.0005%, Pb: ≤0.002%, B: ≤0.008%, Bi: ≤0.0001%, with the remainder being Ni.

[0041] In the marine combustion chamber of the present invention, the first cavity 12, the second cavity 13, and the third cavity 14 are formed within the combustion chamber body 11, and the first cavity 12 and the third cavity 14 are both open to the outside. This makes the internal cavity of the marine combustion chamber 1 complex and the internal flow channel curved, thereby preventing the fuel gas from passing through the marine combustion chamber quickly and directly, causing the fuel gas to generate turbulence in the combustion chamber body 11, prolonging the residence time of the fuel gas in the combustion chamber body 11, and making it more conducive to meeting the application requirements of the marine combustion chamber.

[0042] More importantly, the powder material selected is NiCr20TiAl alloy. NiCr20TiAl alloy is a high-temperature alloy with a nickel-chromium matrix and added aluminum and titanium to form a γ′ phase dispersion strengthening. It exhibits good creep resistance and oxidation resistance between 650 and 850℃. This alloy has good cold and hot working properties, and its main products include hot-rolled, forged bars, cold-drawn bars, hot-rolled plates, cold-rolled plates, strips, and ring parts. It is a metal powder with good heat resistance and fatigue resistance. This alloy can be used to manufacture rotor blades, guide vane supports, sector mounting rings, bolts, blade locking plates, and other components for aero-engines. In addition, it can also be used to manufacture fasteners and blades for automobile engines, as well as valves and shafts for trains. In recent years, with the development of the shipbuilding industry both domestically and internationally, this alloy has been widely used in the manufacture of valves for ship engines. The γ′ phase is the most important strengthening phase in NiCr20TiAl, significantly affecting the creep properties of the NiCr20TiAl alloy. More importantly, there is no precedent for the application of NiCr20TiAl alloy powder in the field of additive manufacturing metal 3D printing. Research on its application directions and material properties has not been conducted, and there are no readily available processes or technical references. The mass percentage composition of the aforementioned NiCr20TiAl alloy was developed specifically for the structure of the aforementioned marine combustion chamber. It is a new NiCr20TiAl alloy that can improve the rigidity, strength, and service life of marine combustion chambers.

[0043] Furthermore, in order to generate more turbulence in the combustion chamber body 11 and prolong the residence time of the fuel gas in the combustion chamber body 11, the angle between the axis of the second cavity 13 and the axis of the first cavity 12 is 17.9 degrees, and the angle between the axis of the third cavity 14 and the axis of the first cavity 12 is 65.5 degrees.

[0044] Furthermore, in order to generate more turbulence in the fuel gas in the combustion chamber body 11 and prolong the residence time of the fuel gas in the combustion chamber body 11, the volumes of the first cavity 12, the second cavity 13 and the third cavity 14 gradually decrease in sequence.

[0045] like Figure 1 As shown, the present invention provides an SLM molding method for manufacturing the above-mentioned marine combustion chamber, comprising the following steps:

[0046] Alloy selection steps: The particle size of NiCr20TiAl alloy powder is 15-53μm;

[0047] Printing preparation steps: Load NiCr20TiAl alloy powder into the powder supply chamber of the 3D printer, load the substrate to support the 3D printed product into the forming chamber of the 3D printer, level and preheat the substrate. The preheating temperature of the substrate is 80-150℃. Pre-lay a layer of NiCr20TiAl alloy powder with a thickness of 50μm on the substrate.

[0048] Model slicing steps: After importing the 3D model of marine combustion chamber 1 into the slicing software, perform layer processing, export the corresponding 2D graphics of each layer, and input the preset printing process parameters.

[0049] Laser forming steps: The oxygen content in the forming chamber is ≤1000ppm, the powder layer thickness is 50μm, the laser power is 100-300W, the scanning speed is 800-1200mm / s, the scanning interval is 0.08-1.2mm, the scanning strategy is strip scanning, the width of the strip is 10mm, the starting angle is 57°, and the layer-by-layer rotation angle is 67°;

[0050] Surface treatment steps: Remove the support between the marine combustion chamber 1 and the substrate, and then perform surface sandblasting on the marine combustion chamber 1 until the surface roughness of the marine combustion chamber 1 meets the preset production standard.

[0051] In the SLM molding method of the present invention

[0052] like Figure 1 , Figure 2 As shown, based on this, the present invention has developed a set of superior SLM process parameters for NiCr20TiAl alloy powder, which reduces the generation of internal defects and enables the mechanical properties of the product to exceed those of traditional forgings, thereby meeting the application requirements of marine combustion chambers. Therefore, the SLM forming method for manufacturing marine combustion chambers of the present invention manufactures a marine combustion chamber 1 that effectively reduces the generation of internal defects and greatly improves mechanical performance indicators through the following steps:

[0053] Alloy selection steps: The particle size of the NiCr20TiAl alloy powder is 15-53 μm. The mass percentage composition of the NiCr20TiAl alloy is as follows: Cr: 18-21%, Al: 1.0-1.8%, Ti: 1.8-2.7%, Co: ≤2.0%, Fe: ≤1.5%, Mn: ≤0.4%, Si: ≤0.8%, P: ≤0.02%, Cu: ≤0.2%, C: 0.04-0.1%, S: ≤0.015%. The powder particle size and composition of NiCr20TiAl alloy were selected to account for the complex structure and special application scenarios of marine combustion chambers. This selection aims to make the formed marine combustion chamber more compact and homogeneous, which is beneficial for subsequent laser forming and surface treatment steps to reduce internal defects of the marine combustion chamber 1 and improve the mechanical properties of the printed sample.

[0054] Printing preparation steps: Load NiCr20TiAl alloy powder into the powder supply chamber of the 3D printer, load the substrate to be carried by the 3D printed product into the forming chamber of the 3D printer, level and preheat the substrate. The preheating temperature of the substrate is 80-150℃. Pre-lay a layer of NiCr20TiAl alloy powder with a thickness of 50μm on the substrate. Preheating the substrate and pre-laying the powder helps the printed product to be stably formed on the substrate.

[0055] Model slicing steps: After importing the 3D model of marine combustion chamber 1 into the slicing software, perform layer processing, export the corresponding 2D graphics of each layer, and input the preset printing process parameters.

[0056] Laser forming steps: such as Figure 3As shown, the oxygen content in the forming chamber is ≤1000ppm, the powder layer thickness is 50μm, the laser power is 100-300W, the scanning speed is 800-1200mm / s, the scanning spacing is 0.08-1.2mm, the scanning strategy is strip scanning, the strip width is 10mm, the starting angle is 57°, and the layer-by-layer rotation angle is 67°, that is, the nth layer is scanned at 57°, and the (n+1)th layer is scanned at 57+67=124°. Selective laser melting 3D printers are used to achieve 3D printing of NiCr20TiAl alloy. Selective laser melting 3D printers, according to the above process parameters, directly melt and solidify the alloy powder under the thermal action of the laser beam to form metal parts with good metallurgical bonding and high precision. This is particularly suitable for manufacturing complex thin-walled precision components that are difficult to achieve with traditional processing techniques. The main characteristics of complex thin-walled precision components are thin walls, complex internal cavities, and curved internal flow channels. At the same time, due to the high cooling rate unique to SLM technology, a wide range of non-equilibrium solidification phenomena are included in the cooling process, which makes the molded parts of the marine combustion chamber 1 have a fine and dense structure, uniform composition, and excellent performance.

[0057] Surface treatment steps: Remove the support between the marine combustion chamber 1 and the substrate, and then perform surface sandblasting on the marine combustion chamber 1 until the surface roughness of the marine combustion chamber 1 meets the preset production standard.

[0058] Therefore, the marine combustion chamber of NiCr20TiAl alloy and the SLM forming method of the present invention, based on the structure of the marine combustion chamber and the new component characteristics of NiCr20TiAl alloy, can shorten the processing cycle, effectively reduce the generation of product defects, and improve the mechanical performance indicators of the product compared with traditional casting, forging and machining processes, thereby meeting the application requirements of marine combustion chambers.

[0059] The laser forming steps described above also include: using a laser to selectively melt and form NiCr20TiAl alloy powder according to a preset scanning path; after each printing layer is completed, the substrate is lowered by 50 μm, and another layer of NiCr20TiAl alloy powder is deposited on the substrate, and the selective melting and forming is repeated until all printing layers are completed.

[0060] Because 304 stainless steel is heated evenly and has relatively good rigidity, the above-mentioned substrate is made of 304 stainless steel.

[0061] The laser forming step further includes: filling the forming chamber of the 3D printer with a protective gas, wherein the forming chamber is located within the forming chamber.

[0062] like Figure 4As shown, the SLM forming method also includes a product inspection step: observing the cut surface of the printed sample using a metallographic microscope. Specifically, after metallographic polishing, the sample is examined under a metallographic microscope (magnification 50x) and no large pores or defects are observed within the observation range, with an overall density of at least 99.99%.

[0063] The SLM forming method further includes a specimen stretching step: tensile tests are performed on the forged specimen and the printed specimen respectively, wherein both the forged specimen and the printed specimen can be heat-treated.

[0064] Specifically, referring to the national standard GB / T228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature", the test results of the above-mentioned printed specimens are shown in the table below:

[0065]

[0066] The test results of the above forged samples are shown in the table below:

[0067]

[0068] Since the yield strength is approximately equivalent to the specified plastic elongation strength, the mechanical properties of the printed sample are superior, indicating that the mechanical properties of the marine combustion chamber 1 are significantly improved, and its performance is better than that of the product manufactured by forging.

[0069] In summary, based on the structure of marine combustion chambers and the novel compositional characteristics of NiCr20TiAl alloy, this invention, compared to traditional casting, forging, and machining processes, can shorten the processing cycle, effectively reduce product defects, and improve the mechanical properties of the product, thereby meeting the application requirements of marine combustion chambers. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0070] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A marine combustion chamber made of NiCr20TiAl alloy, characterized in that, include: The combustion chamber body (11) has a first cavity (12), a second cavity (13) and a third cavity (14) connected in sequence inside the combustion chamber body (11), and the first cavity (12) and the third cavity (14) are both open to the outside; The NiCr20TiAl alloy has the following composition by mass percentage: Cr: 18-21%, Al: 1.0-1.8%, Ti: 1.8-2.7%, Co:≤2.0%, Fe:≤1.5%, Mn:≤0.4%, Si:≤0.8%, P:≤0.02%, Cu:≤0.2%, C:0.04-0.1%, S:≤0.015%, Ag:≤0.0005%, Pb:≤0.002%, B:≤0.008%, Bi:≤0.0001%, the remainder being Ni; the angle between the axis of the second cavity (13) and the axis of the first cavity (12) is 17.9 degrees, and the angle between the axis of the third cavity (14) and the axis of the first cavity (12) is 65.5 degrees; the volumes of the first cavity (12), the second cavity (13), and the third cavity (14) gradually decrease in size; the above-mentioned marine combustion chamber is manufactured using the SLM molding method.

2. An SLM molding method for manufacturing a marine combustion chamber as described in claim 1, characterized in that, Includes the following steps: Alloy selection steps: The particle size of NiCr20TiAl alloy powder is 15-53μm; Printing preparation steps: Load NiCr20TiAl alloy powder into the powder supply chamber of the 3D printer, load the substrate to support the 3D printed product into the forming chamber of the 3D printer, level and preheat the substrate. The preheating temperature of the substrate is 80-150℃. Pre-lay a layer of NiCr20TiAl alloy powder with a thickness of 50μm on the substrate. Model slicing steps: After importing the three-dimensional model of the marine combustion chamber (1) into the slicing software, perform layer processing, export the two-dimensional graphics corresponding to each layer, and input the preset printing process parameters; Laser forming steps: The oxygen content in the forming chamber is ≤1000ppm, the powder layer thickness is 50μm, the laser power is 100-300W, the scanning speed is 800-1200mm / s, the scanning interval is 0.08-1.2mm, the scanning strategy is strip scanning, the width of the strip is 10mm, the starting angle is 57°, and the layer-by-layer rotation angle is 67°; Surface treatment steps: Remove the support between the marine combustion chamber (1) and the substrate, and then perform surface sandblasting on the marine combustion chamber (1) until the surface roughness of the marine combustion chamber (1) reaches the preset output standard.

3. The SLM molding method according to claim 2, characterized in that: The laser forming step further includes: using a laser to selectively melt and form NiCr20TiAl alloy powder according to a preset scanning path; after each printing layer is completed, the substrate is lowered by 50μm, and another layer of NiCr20TiAl alloy powder is deposited on the substrate, and the selective melting and forming is repeated until all printing layers are completed.

4. The SLM molding method according to claim 2, characterized in that: The substrate is made of 304 stainless steel.

5. The SLM molding method according to claim 2, characterized in that: The laser forming step further includes: filling the forming chamber of the 3D printer with a protective gas, wherein the forming chamber is located within the forming chamber.

6. The SLM molding method according to claim 2, characterized in that: The SLM molding method also includes a product inspection step: observing the cut surface of the printed sample using a metallographic microscope.

7. The SLM molding method according to claim 2, characterized in that: The SLM forming method also includes a sample stretching step: performing a tensile test on the printed sample.

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