Relationship among Microstructure, Defects and Performance of Ti60 Titanium Alloy Fabricated by Laser Solid Forming

Abstract

Abstract The relationship among the microstructure, the defects and the performance of the Ti60 alloy samples fabricated by the process of laser solid forming (LSF) was studied, The results indicate that for Ti60 alloy the laser power input has a remarkable effect on the microstructure of LSF samples. Concretely a large power input forms a Widmanstatten microstructure, while a small power input causes a basket weave microstructure. The stress rupture property of the Widmanstatten structure is significantly lower than that of the basketweave structure, the former shows obvious intergranular fracture, while the later shows dimple rupture. At the same time the stress rupture properties are affected by metallurgy defects such as porosities. When the gas atomized powder (powder B) is used as cladding materials, the porosities will be formed within the microstructure of LSF Ti60. When the plasma rotation electrode preparation powder (powder A) is used, there is no such defects observed. The high temperature endurance test results show that the rupture life will significantly decrease from more than 100 h (samples deposited with powder A) to less than 25 h (samples deposited with powder B).