自然科学版 英文版
自然科学版 英文版
自然科学版 英文版
自然科学版 英文版
英文版编委
自然科学版 英文版
英文版首届青年编委

您目前所在的位置:首页 - 期刊简介 - 详细页面

中南大学学报(英文版)

Journal of Central South University

Vol. 28    No. 4    April 2021

[PDF Download]    [Flash Online]

    

Microstructure and mechanical property of additively manufactured NiTi alloys: A comparison between selective laser melting and directed energy deposition
ZHENG Dan(郑聃)1, LI Rui-di(李瑞迪)1, YUAN Tie-chui(袁铁锤)1, XIONG Yi(熊熠)1, SONG Bo(宋波)2, WANG Jia-xing(汪嘉兴)3, SU Ya-dong(苏亚东)3

1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China;
3. Shenyang Aircraft Design and Research Institute, Shenyang 110035, China

Abstract:NiTi shape memory alloy (SMA) with nominal composition of Ni 50.8 at% and Ti 49.2 at% was additively manufactured (AM) by selective laser melting (SLM) and laser directed energy deposition (DED) for a comparison study, with emphasis on its phase composition, microstructure, mechanical property and deformation mechanism. The results show that the yield strength and ductility obtained by SLM are 100 MPa and 8%, respectively, which are remarkably different from DED result with 700 MPa and 2%. The load path of SLM sample presents shape memory effect, corresponding to martensite phase detected by XRD; while the load path of DED presents pseudo-elasticity with austenite phase. In SLM sample, fine grain and hole provide a uniform deformation during tensile test, resulting in a better elongation. Furthermore, the nonequilibrium solidification was studied by a temperature field simulation to understand the difference of the two 3D printing methods. Both temperature gradient G and growth rate R determine the microstructure and phase in the SLM sample and DED sample, which leads to similar grain morphologies because of similar G/R. While higher G×R of SLM leads to a finer grain size in SLM sample, providing enough driving force for martensite transition and subsequently changing texture compared to DED sample.

 

Key words: Ni50.8Ti49.2 shape memory alloy; additive manufacturing; selective laser melting; laser directed energy deposition; mechanical properties

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
版权所有:《中南大学学报(自然科学版、英文版)》编辑部
地 址:湖南省长沙市中南大学 邮编: 410083
电 话: 0731-88879765(中) 88836963(英) 传真: 0731-88877727
电子邮箱:zngdxb@csu.edu.cn 湘ICP备09001153号