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

摘要:

研究了激光立体成形Ti60合金的缺陷及微观组织对于性能的影响。结果表明, 激光功率对于激光成形试样的微观组织有明显的影响，大激光功率会形成魏氏组织，小功率则会形成网篮组织。魏氏组织的持久性能显著的低于网篮组织，其表现为脆性沿晶断裂, 而网篮组织则为韧性断裂。同时冶金缺陷也会影响其持久性能。采用气雾化法制备的粉末（粉末B）作为成形粉末在成形过程中会形成气孔 ，而采用旋转电极法制备的粉末（粉末A）则无气孔产生。相较于无气孔的试样（采用粉末A制备的试样），当存在气孔（采用粉末B制备的试样）时其高温持久性能会由100 h降至25 h

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)