Method for assisting dual wires in additive in-situ synthesis of NiTi shape memory alloy based on electron beam scanning

Abstract

The invention provides a method for assisting dual wires in additive in-situ synthesis of a NiTi shape memory alloy based on electron beam scanning. The method comprises the following steps: determining a deposition path of a target NiTi alloy component; taking a pure Ni wire and a pure Ti wire as printing wire materials, taking a NiTi alloy plate as an additive substrate, and performing fixing; determining the spatial positions of the pure Ni wire and the pure Ti wire in a vacuum chamber; starting a vacuum pump set; setting electron beam fuse wire additive manufacturing parameters, and controlling electron beam deflection scanning; and determining the wire feeding speed of the pure Ni wire and the pure Ti wire according to the target NiTi alloy component, performing layer-by-layer printing according to the set deposition path, and obtaining the target NiTi alloy component after all layers are completed. According to the method, the NiTi alloy component which is high in purity, homogeneous, compact and excellent in performance can be flexibly and efficiently prepared according to the requirements of the components.

Description

technical field [0001] The invention belongs to the technical field of additive manufacturing, and in particular relates to a method for in-situ synthesis of NiTi shape memory alloys based on electron beam scanning-assisted twin-wire additives. Background technique [0002] As an advanced smart material, NiTi alloy has excellent shape memory effect and superelasticity, and has been widely valued and used in aerospace and biomedical fields. However, due to the poor processability of NiTi alloys, the traditional manufacturing process cannot meet the production needs of complex and customized NiTi alloy structures. Emerging frontier research areas. However, when using pre-alloyed raw materials to add materials, there are problems such as high manufacturing cost, unavoidable element burning, narrow composition range and single functional properties, which have long restricted its development. [0003] In recent years, the idea of ​​additive manufacturing in situ synthesis of N...

AI Technical Summary

Problems solved by technology

However, at present, porosity, oxidation, and uneven structure are technical problems that need to be solved urgently in the in-situ synthesis of NiTi alloy components in additive manufacturing.

Existing work has shown that it is difficult to flexibly control the Ni / Ti atomic ratio in real time with the powder-based additive process, and its parts currently have obvious pore defects, low tissue density, and poor mechanical properties; pure Ni and pure When in situ synthesis of NiTi alloy by Ti wire arc, due to the lack of effective molten pool stirring means, the molten metal is mixed unevenly inside the molten pool, resulting in uneven microstructure and structural properties that cannot meet the requirements of use; and the increase in non-vacuum conditions Due to the limited atmosphere protection ability, impurity elements such as O, C, and N can easily enter the deposition layer and form harmful phases such as oxides and carbides, which will damage the functional properties of NiTi alloys.

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