A method for electron beam 4D printing of titanium nickel hafnium shape memory alloy heat exchange components

Abstract

The present application relates to shape memory alloy 4D printing technical field, specifically to a method for 4D printing of titanium nickel hafnium shape memory alloy heat exchange component based on electron beam, according to the application demand of the industrial field to the medium temperature intelligent heat exchange, the variable runner intelligent heat exchange component is designed, the electron beam 4D printing technology is used to select the titanium nickel hafnium shape memory alloy heat exchange component model, the model is composed of front-end intelligent control switch valve and rear main body heat exchange runner. The titanium nickel hafnium shape memory alloy heat exchange component is treated after processing to play the role of intelligent control and improve the heat exchange efficiency.

Description

TECHNICAL FIELD

[0001] The application relates to the field of 4D printing of shape memory alloys, in particular to a method for 4D printing of a titanium-nickel-hafnium shape memory alloy heat exchange component based on an electron beam. BACKGROUND

[0002] With the improvement of the performance of industrial equipment, the temperature of the power end part is higher and higher, and new requirements are put forward for the temperature resistance of the heat exchange component. At the same time, in order to improve the efficiency of heat exchange, the original non-adaptive intelligent heat exchange component also needs to be improved. The titanium-nickel-hafnium shape memory alloy is a temperature-resistant intelligent solid-state phase change material developed on the basis of the titanium-nickel shape memory alloy, which can provide material selection for the intelligent control of the heat exchange component.

[0003] The 4D printing adopts the mode of point-by-point scanning melting, layer-by-layer scanning lapping and layer-by-layer scanning accumulation, which can selectively melt the titanium-nickel-hafnium shape memory alloy pre-alloy powder with shape memory effect and then cool and solidify into the three-dimensional graphic structure metal entity required by us, so that the integration of the front-end intelligent on-off valve and the main flow channel of the heat exchange component can be realized, and the problem of difficult machining of the titanium-nickel-hafnium shape memory alloy can be avoided. The process control of 4D printing will affect the performance of the formed parts, and there is no related technology report at home and abroad. SUMMARY

[0004] The purpose of the application is to provide a method for 4D printing of a titanium-nickel-hafnium shape memory alloy heat exchange component based on an electron beam, to solve the forming process of the medium-temperature intelligent heat exchange component, and to improve the overall heat exchange performance and efficiency of the hot end part in the field of industry.

[0005] In order to achieve the above purpose, the technical scheme of the application is:

[0006] A method for 4D printing of a titanium-nickel-hafnium shape memory alloy heat exchange component based on an electron beam, the heat exchange component is composed of a front-end intelligent control on-off valve and a rear-end main flow channel, and the specific process is as follows:

[0007] (1) According to the actual needs of the specific parts in the industrial field, the size, shape and structure of the heat exchange component model can be adjusted according to the individual needs;

[0008] (2) Using three-dimensional design software and 4D printing special software, a 4D printing model is designed according to the heat exchange component model, and the designed model is printed out by using titanium-nickel-hafnium shape memory alloy pre-alloy powder by electron beam 4D printing;

[0009] 4D printing is performed by electron beam selective melting, and a titanium-nickel-hafnium shape memory alloy heat exchange component with good performance is prepared by adjusting the combination of focus offset (FO) and speed function (SF), wherein the FO is -60-40 mA, and the SF is 0-240 mm.s -1 ;

[0010] (3) The shaped heat exchange component is post-processed, and has the function of intelligently controlling the heat exchange fluid flow channel.

[0011] The method for printing the titanium-nickel-hafnium shape memory alloy heat exchange component based on the electron beam 4D printing, the component ratio of the titanium-nickel-hafnium pre-alloy powder used is changed according to the actual use environment temperature requirement, and the phase transition temperature range of the titanium-nickel-hafnium shape memory alloy is 20-500 DEG C.

[0012] The method for printing the titanium-nickel-hafnium shape memory alloy heat exchange component based on the electron beam 4D printing, the titanium-nickel-hafnium pre-alloy powder used is prepared by a crucible-free gas atomization method, and the particle size range is 45-110 mu m.

[0013] The method for printing the titanium-nickel-hafnium shape memory alloy heat exchange component based on the electron beam 4D printing, when the electron beam selective melting 4D printing is performed, the printing base plate and the powder layer during the printing process need to be preheated, and the preheating temperature range is 750-850 DEG C.

[0014] The method for printing the titanium-nickel-hafnium shape memory alloy heat exchange component based on the electron beam 4D printing, the shaped heat exchange component needs to be post-processed, and is subjected to constraint or non-constraint heat treatment at 300 DEG C.-700 DEG C. for 3-8 h to regulate the performance.

[0015] The method for printing the titanium-nickel-hafnium shape memory alloy heat exchange component based on the electron beam 4D printing, the printing parameters of the electron beam selective melting are as follows: the vacuum degree of a forming bin is 10 -3 ~10 -5 mbar, the powder layer thickness is 30-90 mu m, the acceleration voltage is 60 kV, the scanning current is 10-20 mA, the scanning rate is 1000 mm / s-2000 mm / s, and the scanning interval is 0.1 mm-0.3 mm.

[0016] The design idea of the application is:

[0017] The method of the application is started from the actual heat exchange requirement of an industrial heat end component, a model that can perfectly cooperate with the whole heat end component is designed according to the actual requirement, the pre-alloy powder in the designed model area is selectively melted by means of 4D printing, point-by-point scanning melting, layer-by-layer scanning lapping and layer-by-layer scanning accumulation, so that the designed model is successfully prepared. And through corresponding processing, a front-end intelligent control medium-temperature heat exchange component is obtained.

[0018] The advantages and beneficial effects of the present application are that:

[0019] 1. The method for printing titanium-nickel-hafnium shape memory alloy heat exchange components based on electron beam 4D printing can solve the problem that conventional methods cannot be used to prepare integrated flow channels and intelligent switch valves.

[0020] 2. The method for printing titanium-nickel-hafnium shape memory alloy heat exchange components based on electron beam 4D printing, the 4D printing process is carried out in a vacuum environment, avoiding the doping of oxygen and other elements.

[0021] 3. The method for printing titanium-nickel-hafnium shape memory alloy heat exchange components based on electron beam 4D printing, the preheating of the electron beam to the substrate and the powder during the printing process can avoid the problem that other printing methods must use similar material substrates. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 4D printing heat exchanger components.

[0023] Figures 2(a)-2(b) 4D printing Ti 29.2 Ni 50.8 Hf 20 Phase transition curve (a), powder morphology (b). In figure 2 (a), the abscissa Temperature (℃) represents the temperature, and the ordinate Heat folw (mW / mg) represents the heat flow.

[0024] Figures 3(a)-3(b) 4D printing Ti 29 Ni 51 Hf 20 Phase transition curve (a), powder morphology (b). In figure 3 (a), the abscissa Temperature (℃) represents the temperature, and the ordinate Heat folw (mW / mg) represents the heat flow.

[0025] Figures 4(a)-4(b) 4D printing Ti 39.6 Ni 50.4 Hf 10 Phase transition curve (a), powder morphology (b). In figure 4 (a), the abscissa Temperature (℃) represents the temperature, and the ordinate Heat folw (mW / mg) represents the heat flow. DETAILED DESCRIPTION

[0026] In the specific implementation process, the application designs corresponding heat exchange component models according to the actual needs of industrial heat end component heat exchange; uses three-dimensional design software and 4D printing special software to design 4D printing models according to customized sizes; uses electron beam selective melting of titanium nickel hafnium pre-alloy powder with shape memory effect for 4D printing; the 4D printed heat exchange component is composed of an intelligent control front-end on-off valve and a rear main flow channel. The formed heat exchange component needs to be post-processed, and the performance is regulated by constrained or unconstrained heat treatment at 300-700 DEG C for 3-8 hours. The constrained heat treatment refers to the heat treatment of the deformed on-off valve after being fixed in a special clamp, and the unconstrained heat treatment refers to the direct heat treatment without using an additional clamp.

[0027] In the following, the application is further described in detail through examples and drawings.

[0028] Example 1

[0029] In this embodiment, the method for electron beam 4D printing of titanium nickel hafnium shape memory alloy heat exchange components is as follows:

[0030] As shown in Figure 1 , the heat exchange component is composed of an intelligent control on-off valve at the front end and a main flow channel at the rear end. According to the actual needs of industrial heat end component heat exchange, UG software is used to design the heat exchange component, the front end is an intelligent control on-off valve structure, and the rear end is a fluid channel. The femoral stem model is processed by 4D printing software and then imported into an electron beam selective melting device. 45-110 μm titanium nickel hafnium pre-alloy powder is prepared by a crucible-free gas atomization method for 4D printing, and the atomic ratio of titanium nickel hafnium is Ti 29.2 Ni 50.8 Hf 20 . The phase transition curve is shown in Fig. 2(a), and the powder morphology is shown in Fig. 2(b).

[0031] The 4D printing method is electron beam selective melting, and the combination of focus offset (FO) and speed function (SF) is adjusted to prepare titanium nickel hafnium shape memory alloy heat exchange components with good performance. The electron beam selective melting printing parameters are as follows: the vacuum degree of the forming bin is 10 -5 mbar, the powder layer thickness is 70 μm, the acceleration voltage is 60 kV, the scanning current is 15 mA, the scanning rate is 1800 mm / s, the scanning interval is 0.2 mm, the preheating temperature of the bottom plate and the powder layer is 790 DEG C, the speed function (SF) is 40 mm / s, and the focus offset (FO) is 20 mA.

[0032] The formed heat exchange component needs post-processing, and can be constrained heat treated at 600℃ for 4h to regulate performance, and has the function of intelligently controlling the heat exchange fluid channel.

[0033] Example 2

[0034] In this embodiment, the method for electron beam 4D printing of titanium-nickel-hafnium shape memory alloy heat exchange component is as follows:

[0035] As shown in Figure 1 , the heat exchange component is composed of a front-end intelligent control switch valve and a rear-end main body flow channel. According to the actual needs of industrial heat exchange components, UG software is used to design the heat exchange component, the front-end is an intelligent control switch valve structure, and the rear-end is a fluid channel. The femoral stem model is processed by 4D printing software and imported into the electron beam selective melting equipment. 45-110μm titanium-nickel-hafnium pre-alloy powder is prepared by using the crucible-free gas atomization method for 4D printing, and the atomic ratio of titanium-nickel-hafnium is Ti 29 Ni 51 Hf 20 , the phase transition curve is shown in Fig. 3(a), and the powder morphology is shown in Fig. 3(b).

[0036] The 4D printing method is electron beam selective melting, and the combination of focus offset (FO) and speed function (SF) is used to prepare titanium-nickel-hafnium shape memory alloy heat exchange components with good performance. The electron beam selective melting printing parameters are as follows: the vacuum degree of the forming bin is 10 -5 mbar, the powder layer thickness is 70μm, the acceleration voltage is 60kV, the scanning current is 15mA, the scanning rate is 1800mm / s, the scanning interval is 0.2mm, the preheating temperature of the bottom plate and the powder layer is 790℃, the speed function (SF) is 60mm / s, and the focus offset (FO) is 15mA.

[0037] The formed heat exchange component needs post-processing, and can be constrained heat treated at 500℃ for 6h to regulate performance, and has the function of intelligently controlling the heat exchange fluid channel.

[0038] Example 3

[0039] In this embodiment, the method for electron beam 4D printing of titanium-nickel-hafnium shape memory alloy heat exchange component is as follows:

[0040] As shown in Figure 1As shown, the heat exchange component is composed of a front-end intelligent control switch valve and a rear-end main flow channel. According to the actual needs of the heat exchange of the industrial heat end component, the heat exchange component is designed by using UG software, the front end is an intelligent control switch valve structure, and the rear end is a fluid channel. After the femoral stem model is processed by 4D printing software and imported into the electron beam selective melting equipment, 45-110 mu m titanium nickel hafnium pre-alloy powder is prepared by using a crucible-free gas atomization method for 4D printing, and the atomic ratio of titanium nickel hafnium is Ti 39.6 Ni 50.4 Hf 10 , the phase transition curve is shown in Fig. 4(a), and the powder morphology is shown in Fig. 4(b).

[0041] The 4D printing method is electron beam selective melting, and the combination of focus offset (FO) and speed function (SF) is adjusted to prepare a titanium nickel hafnium shape memory alloy heat exchange component with good performance. The electron beam selective melting printing parameters are: the vacuum degree of the forming bin is 10 -4 mbar, the powder layer thickness is 50 mu m, the acceleration voltage is 60 kV, the scanning current is 18 mA, the scanning rate is 1500 mm / s, the scanning interval is 0.1 mm, the preheating temperature of the bottom plate and the powder layer is 820 DEG C, the speed function (SF) is 55 mm / s, and the focus offset (FO) is 25 mA.

[0042] The formed heat exchange component needs to be post-processed, and can be heat treated at 300 DEG C for 8h without constraint to regulate the performance, and has the function of intelligent control of the heat exchange fluid flow channel.

[0043] The results of the embodiment show that the application designs a variable flow channel intelligent heat exchange component, uses electron beam 4D printing technology to selectively melt a titanium nickel hafnium shape memory alloy heat exchange component model, the model is composed of a front-end intelligent control switch valve and a rear-end main heat exchange flow channel. The titanium nickel hafnium shape memory alloy heat exchange component is intelligentized after post-processing, which improves the heat exchange efficiency.

Claims

1. A method for 4D printing titanium-nickel-hafnium shape memory alloy heat exchange components using electron beam, characterized in that, The heat exchange component consists of a front-end intelligently controlled on / off valve and a rear-end main flow channel. The specific process is as follows: (1) The size, shape and structure of the heat exchange component model can be adjusted according to the actual needs of specific parts in the industrial field, and are completely customized. (2) Using 3D design software and 4D printing software, a 4D printing model is designed based on the heat exchange component model. The designed model is printed using electron beam 4D printing with titanium-nickel-hafnium shape memory alloy pre-alloyed powder. The phase transition temperature range of titanium-nickel-hafnium shape memory alloys varies from 20℃ to 500℃ depending on the alloy composition. 4D printing utilizes electron beam selective melting, and high-performance titanium-nickel-hafnium shape memory alloy heat exchange components are fabricated by adjusting the combination of focus offset (FO) and speed function (SF). FO ranges from 15 to 25 mA, and SF ranges from 40 to 60 mm·s. -1 In electron beam selective melting 4D printing, the printing substrate and powder layer need to be continuously preheated during the printing process, with a preheating temperature range of 790–820℃. The electron beam selective melting printing parameters are: a vacuum level of 10 in the forming chamber. -3 ~10 - 5 mbar, powder layer thickness of 30-90 μm, accelerating voltage of 60 kV, scanning current of 10-20 mA, scanning rate of 1000 mm / s-2000 mm / s, and scanning spacing of 0.1 mm-0.3 mm; (3) The formed heat exchange components are post-treated and kept at 300℃~700℃ for 3h~8h for constrained or unconstrained heat treatment to regulate their performance and have the function of intelligent control of heat exchange fluid flow channels.

2. The method for electron beam 4D printing of titanium-nickel-hafnium shape memory alloy heat exchange components according to claim 1, characterized in that, The composition ratio of the titanium-nickel-hafnium pre-alloyed powder used varies depending on the actual operating temperature requirements.

3. The method for electron beam 4D printing of titanium-nickel-hafnium shape memory alloy heat exchange components according to claim 1, characterized in that, The titanium-nickel-hafnium pre-alloyed powder used was prepared by crucibleless gas atomization, with a particle size range of 45–110 μm.

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