The Effect of Vacuum and Low Temperature Environment on Laser Wire Additive Manufacturing

Abstract

In response to the technical requirements for in-orbit maintenance and in-situ additive manufacturing in extreme space environments, this paper investigates the impact of vacuum low-temperature environment on laser additive manufacturing of metal wire materials. A metal laser direct writing additive manufacturing experimental device was built, and researches were conducted on the metal wire additive manufacturing process in vacuum and low temperature(-120℃) environments in a simulated space environment experimental platform on the ground. Taking typical titanium alloy thin-walled parts as the analysis object, the differences in mechanical properties and metallographic structure of the samples formed in vacuum low-temperature environment and pure vacuum environment were compared and analyzed. Research has found that: 1) The comprehensive mechanical properties of tensile specimens under vacuum and low-temperature environmental conditions have been improved compared to formed specimens under vacuum conditions, mainly reflected in the deposition direction of tensile specimens. The tensile strength in this direction has increased by 78.8MPa, the elongation has increased by 7.1%, and the anisotropy of mechanical properties has been effectively alleviated compared to the former; 2) The average overall grain size of the formed sample under vacuum and low temperature environment is 9.21μm, which is significantly smaller than the average grain size of the vacuum formed sample. The refinement of grain size also contributes to the improvement of the comprehensive mechanical properties of the sample; 3) Although printed samples exhibit certain texture characteristics under both environmental conditions, the maximum texture strength (49.03) of printed samples in vacuum and low-temperature environments is weaker than that of printed samples in vacuum environments (58.85). The weakening of texture strength greatly alleviates the anisotropy of mechanical properties of printed samples. The above research content provides important references for future metal additive manufacturing and component repair in extreme space environments.

Keywords: Space manufacturing, extreme manufacturing, vacuum and low-temperature environment manufacturing, metal additive manufacturing, laser direct writing manufacturing