Selective laser melting of NiTi alloy with superior tensile property and shape memory effect

Zhiwei Xiong¹，Zhonghan Li¹，Zhen Sun¹，Shijie Hao¹，Ying Yang¹，Meng Li²，Changhui Song³，Ping Qiu¹，Lishan Cui¹

1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum2. Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology3. School of Mechanical & Automotive Engineering, South China University of Technology

摘 要：It is a challenge to develop complex-shaped Ni Ti shape memory alloy parts by traditional processing methods, due to the poor machinability of Ni Ti alloy. It is reported that selective laser melting（SLM） of additive manufacturing could overcome this problem. However, the reported SLM-produced Ni Ti exhibits poor tensile ductility due to the inner defects and adverse unidirectional columnar grains from SLM process. In this work, the defect-less SLM-Ni Ti with nondirective columnar grains was fabricated by optimizing the intraformational laser scanning length and interformational laser scanning direction. The obtained lath-shaped SLM-Ni Ti sample exhibits tensile strain of 15.6%, more than twice of the reported maximum result（■）. Besides, the SLM-Ni Ti part with complex geometry displays a shape memory recovery of 99% under compressive deformation of 50%.

关键词：