Laser Selective Shock-Additive Composite Manufacturing Method for Three-dimensionally Reinforced Shape Memory Alloys

Abstract

The invention discloses a laser selective area impact-additive composite manufacturing method for a three-dimensionally reinforced shape memory alloy, which comprises the following steps: designing a three-dimensional laser shock-strengthened structural model of a component, generating impact-strengthened path information for each layer; the additive manufacturing control system based on The alloy component model and process parameters are used to manufacture a single deposition layer; the laser shock strengthening control system extracts the impact strengthening path information of this layer, applies preheating to the deposited component as required, and performs laser shock treatment; and so on until the entire component forming and manufacture. By controlling the graphic structure and process parameters of the laser shock, the invention can accurately control the deformation state of austenite and martensite in the three-dimensional direction and the forward and reverse phase transformation of martensite in the shape memory alloy in situ, and realize the solid phase transformation of the alloy. , high-efficiency, high-quality integrated control and optimization of superelasticity and shape memory effects, providing new manufacturing methods and means for complex structures and high-performance shape memory alloys.

Description

technical field [0001] The invention relates to the technical field of laser additive manufacturing, in particular to a laser selective impact-additive composite manufacturing method for a three-dimensionally reinforced shape memory alloy. Background technique [0002] Shape memory alloys (Shape Memory Alloys) can not only achieve self-compiled and controllable changes in the shape of components through superelasticity and shape memory effects, but also maintain excellent mechanical properties such as load bearing, force transmission, and connection. Among them, the essence of the superelasticity and memory effect of shape memory alloys is the interaction between the high-order austenite (A) parent phase and the low-order martensite (M) induced by excitation (temperature, stress, electromagnetic field, etc.). Crystallographically reversible thermoelastic martensite transformation and reorientation between polymorphic martensite. Therefore, manipulating the solid-state phase...

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Problems solved by technology

However, there are still the following problems: ①Difficult to control the microstructure: the shape memory effect of most shape memory alloys comes from the forward and reverse phase transformation of martensitic in the alloy, but the complex thermodynamic environment of additive manufacturing leads to microstructure Uncertainty of characteristics and low controllability of regulation means

③Metallurgical defects: Additive manufacturing is an unbalanced process of rapid solidification and shrinkage, cyclic heating and cooling. The uneven temperature field generated by local high-energy heat input will cause the molten pool to bear complex thermal stress and microstructure during the solidification and subsequent cooling stages. Stress and residual stress and their mutual coupling, so metallurgical defects such as pores, cracks, and warpage are easily produced under the thermal cycle and tensile stress of laser rapid melting

However, based on laser shock strengthening technology-assisted additive composite manufacturing of shape memory alloys, the relevant reports on the solid state phase transition process, solidification crystallization behavior and shape memory effect regulation of the alloy through laser shock wave force are still blank.

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