An electrically assisted preparation method for a large-area array of micro-grooves with spatially curved thin-walled structures

Abstract

The present invention discloses an electrically assisted preparation method for a space-bending thin-walled structural part with continuous large-area array micro-grooves of a difficult-to-deform material, and specifically relates to a micro-groove roll forming method for difficult-to-deform materials such as titanium alloy, high-strength aluminum alloy, and high-temperature alloy foil. The method comprises the following steps: passing a pulse current with variable electrical parameters into the difficult-to-deform metal foil, giving a micro-groove forming depth h, and maintaining the spatial difference distribution T of the temperature field on the surface of the sample through a temperature feedback adjustment system and a heat dissipation unit auxiliary means. 0 、T 1 ,…T i …T n‑1 、T n , so that the radius of curvature of the micro-grooves on the foil surface after rebound is differentially distributed along the width direction, and the motor-driven continuous rolling forming can obtain a spatially curved thin-walled structural part with a continuous large-area array of micro-grooves.

Description

Technical Field

[0001] The invention belongs to the field of ultra-thin plate complex structure forming, and in particular relates to an electrically assisted preparation method for a large-area array micro-groove space curved thin-wall structure. Background Art

[0002] The invention belongs to the field of ultra-thin plate complex structure forming, and in particular relates to an electrically assisted preparation method of a hard-to-deform material spatially curved thin-walled structural member with continuous large-area array micro-grooves.

[0003] The heat exchanger with the characteristics of microchannel heat dissipation and mass transfer technology is a high-efficiency, environmentally friendly, energy-saving and lightweight heat sink. Compared with traditional heat exchangers, microchannel heat exchangers have incomparable advantages. Among them, large-scale microchannel heat exchangers are mainly used in civil and defense fields, such as automotive air conditioners, phased array radars, aircraft engine combustion chambers and turbine blades. The internal microchannel structures of large-scale microchannel heat exchangers used in aerospace and other industrial fields are mainly parallel flow and three-dimensional cross-flow. The heat dissipation materials are usually selected from materials with large thermal conductivity such as copper, stainless steel, aluminum alloy and titanium alloy. Taking the strong cooling heat exchanger of hypersonic aircraft engines as an example, it can achieve high-efficiency and rapid deep cooling of high-temperature air, so that the temperature is reduced to the normal working temperature of the aircraft engine. Microchannel heat exchangers are often used to enhance their cooling performance. Generally, microchannel heat exchangers are basic heat exchange units of millimeter or submillimeter level in terms of geometric scale. Most of the micro-scale heat exchange units are thin-walled capillary tubes with a diameter of less than 1mm and a wall thickness of about 0.05mm.

[0004] Common microchannel processing methods mainly include extrusion technology, micro-EDM technology, excimer laser micro-machining technology and precision micro-cutting, but they face problems such as difficult to accurately control the processing size, low material removal rate, and poor processing surface quality. In addition, usually, after micro-scale heat exchange units such as thin-walled tubes are welded into a heat exchanger as a whole, the heat exchanger needs to be bent into a certain shape. In this process, due to the micro-scale heat exchange unit materials such as thin-walled capillaries, it is easy to be twisted and deformed or even damaged, which affects the heat exchange performance of the heat exchanger. Therefore, there is an urgent need for a method that can reduce the damage of bending deformation after forming and efficiently manufacture thin-walled parts with micro-grooves made of difficult-to-deform materials such as titanium alloys.

[0005] After searching, a Chinese invention patent was found: A method for precision stamping of a curved surface metal micro-V-shaped array structure. Publication number: CN 107745026B Application number: 201711241060.2 The invention discloses a "method for stamping a curved surface metal micro-V-shaped array structure". First, according to the stamping process material parameters, the required curved surface curvature and the size parameters of the micro-V-shaped array structure, the deformation of the micro-V-shaped array structure during the stamping process is calculated and predicted; then, according to the deformation, the corresponding micro-V-shaped array structure before deformation is designed and ground on the flat metal sheet; finally, it is quickly formed by stamping. The invention provides a new method for forming curved surface microstructures, which overcomes the shortcomings of directly grinding or cutting microstructures on the curved surface. However, this processing method is aimed at thicker plates, and cold stamping cannot form thin-walled bent parts.

[0006] After searching, a Chinese invention patent was found: Batch hot forming micromachining method for three-dimensional curved surface microstructures. Publication number: CN103232022B Application number: 201310115655.9 The invention discloses a "batch hot forming micromachining method for three-dimensional curved surface microstructures". First, a groove is formed on the substrate wafer; then a thermal gas release agent is added to an aqueous solution of sodium silicate, and after stirring evenly, an appropriate amount is added to the above groove, and then the water is evaporated to remove the water; then the thermoformable wafer and the above substrate wafer are bonded under vacuum or a certain pressure to seal the groove; then the bonded thermoformable wafer and substrate wafer are heated to above the softening temperature of the thermoformable wafer and kept warm, and the gas released by the thermal gas release agent in the groove generates a positive pressure so that the corresponding part of the thermoformable wafer corresponding to the sealed cavity is thermoformed to form a three-dimensional curved surface microstructure, and then cooled and annealed; finally, the substrate wafer is removed. The invention provides a thermoforming method for three-dimensional curved surface microstructures, which overcomes the shortcomings of mass production.

[0007] However, since gas pressure is required to form a three-dimensional curved microstructure, the pressure is difficult to control. In addition, this method has the disadvantages of complex process, long production preparation time, and is not suitable for difficult-to-deform metal materials. Summary of the invention

[0008] The purpose of the present invention is to provide an electrically assisted preparation method for a spatially curved thin-walled structural part with a continuous large-area array of micro-grooves. Aiming at the problem that difficult-to-deform metal materials are difficult to form at room temperature, a pulse current with a certain current density and frequency is passed through a difficult-to-deform metal foil to control the spatial temperature difference distribution during the micro-groove roll forming process of the foil sample, so as to achieve differential distribution of the curvature radius along the width direction after the fillet rebounds during the forming process of the micro-groove thin-walled part, thereby obtaining a continuous large-area array of micro-groove thin-walled structural parts with a certain bending curvature radius.

[0009] The core implementation method of the present invention comprises the following steps:

[0010] (1) Place a hard-to-deform metal foil sample between two forming rollers, adjust the vertical position of the forming rollers to press the foil sample, adjust the position of the conductive roller so that the foil contacts the surface of the conductive roller; adjust the distance between the upper and lower forming rollers to change the roller pressure h and provide the forming depth of the micro grooves;

[0011] (2) A pulse current generator generates a pulse current with a certain current density and frequency, which flows through the forming roller and the foil sample, and forms an electric circuit with the conductive roller and the foil sample of the difficult-to-deform material, generating unevenly distributed Joule heat and a temperature field on the sample surface along the width direction;

[0012] (3) According to the shape requirements of the micro-groove cross section required for the spatial bending of thin-walled structural parts, the downward pressure of the forming roller is adjusted, the forming temperature T is set, and the surface temperature Ti of the foil sample is monitored by an infrared imager. The given forming temperature T and the surface temperature Ti of the foil sample during forming are compared through the temperature feedback adjustment system and the auxiliary means of the heat dissipation unit, and the electrical parameters (current density, pulse width) are adjusted by feedback to maintain the spatial temperature difference distribution on the surface of the foil sample. In this way, the curvature radius of the micro-groove after the rebound is obtained. The curvature radius of the thin-walled part is changed during the roller forming process;

[0013] (4) The upper and lower forming rollers are rotated synchronously by a motor-driven rotating shaft. The friction between the rollers and the surface of the foil sample is used to keep the foil feeding along the driving direction. The continuous roll forming is gradually extended to the entire foil area, and a spatially curved thin-walled structural part with a continuous large-area array of micro-grooves can be obtained.

[0014] Optionally, the foil sample thickness is not greater than 0.1 mm, the ratio of the depth to the width of the formed micro-grooves is greater than 1.0, the micro-groove width is 0.2-0.5 mm, the number of micro-grooves distributed in parallel arrays along the width direction is greater than 15, and the maximum directional dimension of the thin-walled structural part is greater than 300 mm.

[0015] Optionally, the spatially curved thin-walled part containing array micro-grooves has a single curvature, and the curvature radius of the single curvature along the width direction is not less than 15 mm.

[0016] Optionally, the preparation method is applicable to difficult-to-deform metal foil materials such as titanium alloys, high-strength aluminum alloys, and high-temperature alloys.

[0017] Optionally, in the preparation method, the current density of the electrically assisted rolling of the difficult-to-deform metal foil is 34A / mm2-65A / mm2, and the temperature range of the forming area is 300℃-1200℃.

[0018] Optionally, the forming temperature of the hard-to-deform metal foil is controlled by using a spatial temperature difference temperature field distribution, specifically including:

[0019] The self-resistance heating roll forming temperature T (300℃≤T≤1200℃) is set, and the surface temperature Ti of the foil sample during the rolling process is monitored by an infrared imager. Based on the temperature feedback adjustment system, by comparing Ti and T, if there is a deviation beyond the tolerance (20℃), the regulator will process the deviation signal and then transmit it to the temperature feedback adjustment system. The pulse current parameters (pulse frequency, current pulse width, current density) are adjusted by the pulse current generating device to increase or decrease the Joule heat of the foil sample and keep the forming temperature stable within a certain range;

[0020] According to the uneven temperature distribution of the self-resistance heating foil sample along the width direction, the local heat dissipation unit is used to increase the degree of heat convection between the foil surface and the air by adjusting the speed of the heat dissipation fan, so that the foil surface presents obvious spatial temperature difference distribution T0, T1, ...T along the width direction. i …T n-1 , T n .

[0021] Optionally, the radius of curvature of the micro-groove after the rounded corner rebounds is differentially distributed along the width direction, and its distribution law is controlled and adjusted by the differential temperature field distribution obtained by claim 6, and the specific features are as follows:

[0022] According to the characteristics of plastic deformation of the hard-to-deform metal foil sample at the groove, the local temperature is high during the forming process, and due to the constraint of the mold, it is difficult to have a large springback deformation, which can be ignored;

[0023] According to the geometric relationship of the fillet of the hard-to-deform metal foil sample roll test and the elastic-plastic theory, combined with the strain neutral layer formula, the formula for the rebound angle in the elastic deformation area is obtained: Under high temperature, the yield strength of the hard-to-deform metal foil sample changes σ s = g(T), and the formula for the springback angle of the elastic deformation area under the influence of temperature is obtained: Among them, α and β are the springback angles of the elastic deformation area before and after the temperature influence, σ s is the yield strength of the foil sample at different temperatures, ρ is the given curvature radius, ρ2 is the outer curvature radius after bending, E is the elastic modulus of the foil sample, and t is the thickness of the foil sample;

[0024] According to the geometric relationship of the bending deformation of the foil sample at the rounded groove, the strain is proportional to the pressure h of the forming roller, and ε θ =f(h), according to the plastic strain formula Get the outer diameter of the bend after springback

[0025] According to the neutral layer invariant equation of the hard-to-deform metal foil sample, the curvature radius of the micro-groove corner after rebound is obtained.

[0026] According to the spatial difference distribution state of the foil surface temperature field T0, T1, ...T i …T n-1 , T0, and the curvature radius formula after the rounded corner rebound is used to obtain the difference distribution state of the curvature radius of the micro-groove after the rounded corner rebound along the width direction of the sample. The foil sample presents a certain curvature change ρ0, ρ1, …ρ along the width direction. i …、ρ n-1 , n .

[0027] The present invention adopts pulse current to assist micro-groove rolling forming, and utilizes the uneven distribution of Joule heat temperature generated along the width direction after the foil sample is energized. The temperature feedback adjustment system is used to achieve the spatial difference distribution of the foil surface temperature field. The difference distribution state of the curvature radius along the width direction after the fillet rebounds during the micro-groove forming process is used to achieve the spatial bending forming and curvature radius control of the micro-groove thin-walled parts of difficult-to-deform materials. In general, the technical solution proposed by the present invention has the following advantages compared with the existing forming technology:

[0028] (1) By utilizing the uneven temperature distribution caused by the pulse current passing through the difficult-to-deform metal material and the springback of the formed micro-groove fillet, a thin-walled part with a certain spatial bending curvature radius is obtained, avoiding the subsequent bending forming process.

[0029] (2) The present invention improves the plastic deformation ability of difficult-to-deform materials, reduces flow stress, and improves forming performance through the Joule heat and electroplasticity effects of pulse current assisted forming. It can also improve the formation of micro-grooves during the rolling process, and to a certain extent solves the problem of difficult-to-deform metals being difficult to process and form in the prior art.

[0030] (3) The present invention controls the spatial temperature difference distribution during the foil roll forming process through the combined effect of the temperature feedback adjustment system and the heat dissipation unit, so that the bending degree of the thin-walled part can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1This is a core process diagram of a method for preparing a space-bent thin-walled structural member with continuous large-area array micro-grooves according to the present invention.

[0033] Figure 2 (a) (b) Schematic diagram of the forming process of the thin-walled structure with continuous large-area array microchannel space bending of the present invention

[0034] FIG. 3(a) and (b) are schematic diagrams showing the temperature field control and distribution along the width direction of a continuous large-area array microchannel thin-walled structure during the forming process of Embodiment 1 of the present invention.

[0035] Figure 4 Schematic diagram of a curved thin-walled structure with a continuous large-area array of microchannels obtained by the present invention DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the implementation examples of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] When the micro-groove roll forming is performed on the foil of the difficult-to-deform material to achieve spatial bending deformation, such as Figure 1 As shown, the specific steps mainly include:

[0039] (1) Place a hard-to-deform metal foil sample between two forming rollers, adjust the vertical position of the forming rollers to press the foil sample, adjust the position of the conductive roller so that the foil contacts the surface of the conductive roller; adjust the distance between the upper and lower forming rollers to change the roller pressure h and provide the forming depth of the micro grooves;

[0040] (2) A pulse current generator emits an adjustable pulse current with a certain current density and frequency, which flows through the forming roller and the foil sample, and forms an electric circuit with the conductive roller and the foil sample of the difficult-to-deform material, generating unevenly distributed Joule heat and a temperature field on the sample surface along the width direction;

[0041] (3) According to the shape requirements of the micro-groove cross section required for the spatial bending of thin-walled structural parts, the downward pressure of the forming roller is adjusted, and the speed of the cooling fans on both sides is adjusted through the temperature feedback adjustment system and the auxiliary means of the heat dissipation unit to maintain the spatial difference distribution of the temperature field on the surface of the sample, so as to obtain the difference distribution of the curvature radius of the micro-groove fillet after rebound along the width direction, so as to change the bending curvature of the thin-walled parts during the forming process;

[0042] (4) The upper and lower forming rollers are rotated synchronously by a motor-driven rotating shaft. The friction between the rollers and the surface of the foil sample is used to keep the foil feeding along the driving direction. The continuous roll forming is gradually extended to the entire foil area, and a spatially curved thin-walled structural part with a continuous large-area array of micro-grooves can be obtained.

[0043] As shown in Figure 2(a)(b), the forming device required by the method proposed in the present invention mainly includes the following parts: 1 is a difficult-to-deform metal foil sample to be formed; 2 is an upper forming convex roller whose front end can change position in the vertical direction and is connected to the circuit, 3 is a fixed lower forming concave roller; 4 is an upper conductive roller whose rear end can change position in the vertical direction; 5 is a lower conductive roller that remains fixed, 6 is an infrared thermal imager for monitoring the surface of the sample; 7 is a temperature feedback adjustment system; 8 is a local heat dissipation unit (cooling fan); 9 is a pulse current generating device that can generate a certain pulse current.

[0044] Implementation example 1: For a titanium alloy foil with a composition of 89.335% Ti by mass, 6% Al by mass, and 4% V by mass, the foil width is 60 mm, the thickness is 0.1 mm, the length is 300 mm, the forming roller diameter is 80 mm, the ratio of the depth to the width of the micro-groove on the forming roller is greater than 1.0, the width of the micro-groove is 0.35 mm, the conductive roller diameter is 80 mm, and the number of micro-grooves distributed in a parallel array along the width direction is 18.

[0045] Place the hard-to-deform foil between the forming rollers and the conductive rollers on both sides, adjust the position of the upper forming roller so that the upper and lower forming rollers press the foil tightly, and then adjust the upper conductive roller so that the upper and lower conductive rollers clamp the foil tightly. Adjust the downward pressure h of the upper forming roller, turn on the pulse current generating device, and make the generated pulse current (current density 40A / mm2) flow through the lower conductive roller, the foil and the upper forming roller to form an energized circuit. After 30 seconds of power-on, the temperature of the foil forming area rises to about 800℃, and the upper forming roller moves down a distance, causing the foil blank to deform after power-on. Due to the characteristics of pulse current heating, the surface temperature of the foil is unevenly distributed along the width direction. Through the temperature feedback adjustment system and the auxiliary means of the heat dissipation unit, the speed of the cooling fan is adjusted to 800r / min to maintain the surface temperature field of the foil in a spatially differential distribution state. The schematic diagram of the temperature field control and distribution of the foil along the width direction is shown in Figure 3 (a) (b). The temperature distribution along the width direction roughly shows a trend of 680℃, 720℃, 760℃, 800℃, 840℃, 800℃, 760℃, 720℃, and 680℃. Combined with the spatial difference distribution of the curvature radius after the micro-groove fillet rebounds, the foil sample presents a certain single curvature spatial bending arc. The schematic diagram of the change of the formed structure is shown in Figure 4As shown, the motor-driven continuous roll forming is gradually extended to the entire foil area, so that a spatially curved thin-walled structure with a continuous large-area array of micro-grooves can be obtained.

[0046] By changing the roller pressure h, multiple groups of pulse current assisted rolling tests were carried out, the corresponding electrical parameters were adjusted, the speed of the cooling fan was adjusted, the degree of thermal convection between the foil sample and the air was changed, and the temperature difference distribution in different spaces under multiple groups of electric-assisted rolling tests was obtained, and further more continuous large-area array microchannel thin-walled structural parts with different spatial bending curvature radii were obtained.

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0048] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An electrically assisted preparation method for a large-area array micro-groove space curved thin-wall structure, characterized in that: The following steps are involved: (1) Place the hard-to-deform alloy foil between two forming rollers, adjust the vertical position of the forming rollers to press the hard-to-deform alloy foil, and adjust the position of the conductive roller so that the hard-to-deform alloy foil contacts the surface of the conductive roller; adjust the distance between the upper and lower forming rollers to change the roller pressure h and provide the forming depth of the micro grooves; (2) A pulse current generator emits an adjustable pulse current with a certain current density and frequency, which flows through the forming roller and the difficult-to-deform alloy foil, generating Joule heat and a non-uniform distribution of the surface temperature field of the sample along the width direction, and forms an electric circuit with the conductive roller and the difficult-to-deform alloy foil; (3) According to the shape requirements of the micro-groove cross section required for the spatial bending of thin-walled structural parts, the downward pressure of the forming roller is adjusted, and the spatial difference distribution of the surface temperature field of the difficult-to-deform alloy foil is maintained through the temperature feedback adjustment system and the auxiliary means of the heat dissipation unit. In this way, the curvature radius of the micro-groove fillet after rebound is differentially distributed along the width direction, thereby changing the spatial bending curvature radius of the thin-walled parts during the forming process; (4) The upper and lower forming rollers are rotated synchronously by a motor-driven rotating shaft. The friction between the rollers and the surface of the difficult-to-deform alloy foil is used to keep the difficult-to-deform alloy foil feeding along the driving direction. The continuous roll forming is gradually extended to the entire difficult-to-deform alloy foil area, and a spatially curved thin-walled structural component with a continuous large-area array of micro-grooves can be obtained.

2. The electrically assisted preparation method of a large-area array micro-groove space curved thin-wall structure according to claim 1, characterized in that: The thickness of the difficult-to-deform alloy foil is not more than 0.1mm, the ratio of the depth to the width of the formed micro-groove is greater than 1.0, the width of the micro-groove is 0.2-0.5mm, the number of parallel arrays of micro-grooves along the width direction is greater than 15, and the length direction dimension of the thin-walled structural part is greater than or equal to 300mm.

3. The electrically assisted preparation method of a large-area array micro-groove space curved thin-wall structure according to claim 1, characterized in that: The spatially curved thin-walled part containing array micro-grooves has a single curvature, and the curvature radius of the single curvature along the width direction is not less than 15 mm.

4. The electrically assisted preparation method of a large-area array micro-groove space curved thin-wall structure according to claim 1, characterized in that: The preparation method is applicable to titanium alloys and high-strength aluminum alloys.

5. The electrically assisted preparation method of a large-area array micro-groove space curved thin-wall structure according to claim 1, characterized in that: In the preparation method, the current density of the electrically assisted rolling-pressed difficult-to-deform alloy foil is 34A / mm 2 -65 A / mm 2 , the temperature range of the forming area is 300℃-1200℃.

6. The electrically assisted preparation method of a large-area array micro-groove space curved thin-wall structure according to claim 1, characterized in that: The forming temperature of the difficult-to-deform alloy foil is controlled by the spatial temperature difference temperature field distribution, which includes: Set the self-resistance heating roll forming temperature T (300℃≦T≦950℃), and use an infrared imager to monitor the surface temperature T of the hard-to-deform alloy foil during the rolling process. i , based on the temperature feedback regulation system, by comparing T i If the deviation exceeds the tolerance (20°C), the regulator will process the deviation signal and send it to the temperature feedback regulation system. The pulse current generating device will adjust the pulse current parameters (pulse frequency, current pulse width, current density) to increase or decrease the Joule heat of the difficult-to-deform alloy foil and keep the forming temperature stable within a certain range. According to the uneven temperature distribution of the self-resistance heating hard-to-deform alloy foil along the width direction, the local heat dissipation unit is used to increase the degree of heat convection between the surface of the hard-to-deform alloy foil and the air by adjusting the speed of the heat dissipation fan, so that the surface of the hard-to-deform alloy foil presents a differential temperature field distribution T0, T1, ... T i …T n-1 、T n .

7. The electrically assisted preparation method of a large-area array micro-groove space curved thin-wall structure according to claim 6, characterized in that: After the micro-groove fillet rebounds, the curvature radius presents a differential distribution along the width direction, and its distribution law is adjusted by the spatial temperature difference temperature field distribution control, and the specific characteristics are as follows: According to the plastic deformation characteristics of the hard-to-deform alloy foil at the groove, the local temperature is high during the forming process, and coupled with the mold constraint, it is difficult to have a large springback deformation, which can be ignored; According to the geometric relationship of the fillet of the hard-to-deform alloy foil roll test and the elastic-plastic theory, combined with the strain neutral layer formula, the formula for the springback angle in the elastic deformation area is obtained: ; Under high temperature, the yield strength of the hard-to-deform alloy foil changes , the formula for the springback angle of the elastic deformation area under the influence of temperature is obtained .in, , They are the springback angles of the elastic deformation area before and after the temperature influence, The yield strength of the hard-to-deform alloy foil at different temperatures. For a given radius of curvature, is the outer curvature radius after bending, E is the elastic modulus of the difficult-to-deform alloy foil, and t is the thickness of the difficult-to-deform alloy foil; According to the geometric relationship of bending deformation of micro-groove rounded corners of hard-to-deform alloy foil, the strain is proportional to the pressure of the forming roller. ,get , according to the plastic strain formula , get the outer diameter of the bend after springback ; According to the neutral layer invariant equation of the hard-to-deform alloy foil, the curvature radius of the micro-groove fillet after springback is obtained. ; According to the spatial difference distribution state of the surface temperature field of the difficult-to-deform alloy foil, T0, T1, ... T i …T n-1 、T n According to the formula of the curvature radius after the rounded corner rebound, the distribution state of the curvature radius difference of the micro-groove rounded corner after the rounded corner rebound along the width direction of the hard-to-deform alloy foil is obtained. The hard-to-deform alloy foil presents a certain curvature change ρ0, ρ1, …ρ along the width direction. i …、ρ n-1 , n .

Images