Influence of heat treatments on the mechanical properties of high-quality Ni-rich NiTi produced by powder metallurgical methods

被引：30

作者：

Mentz, Juliane ^{[1
]}

Bram, Martin ^{[1
]}

Buchkremer, Hans Peter ^{[1
]}

Stoever, Detlev ^{[1
]}

机构：

[1] Forschungszentrum Julich, Inst Werkstoffe & Verfahren Energietechn IWV 1, D-52425 Julich, Germany

来源：

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 2008年 / 481卷 / 1-2 C期

关键词：

powder metallurgy; NiTi shape memory alloys; heat treatments; microstructure; tensile tests;

D O I：

10.1016/j.msea.2006.10.215

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

NiTi alloys produced by different powder metallurgical (PM) methods are investigated concerning transformation behavior and shape memory characteristics. Effects of purity, heat treatments and processing conditions are taken into account. It is shown that the deformability of PM-NiTi is increased after a long-term treatment at 1250 degrees C when the two different types of secondary phases resulting from impurities of oxygen and carbon become larger in size, and their distribution is therefore more isolated. In the case of Ni-rich NiTi material, the mechanical behavior is further influenced by the precipitation of metastable phases (Ni4Ti3) at intermediate temperatures (350 and 450 degrees C), which reduce the deformability, again resulting in reduced elongations at fracture. The stress level and the elongation at fracture are reduced by a residual porosity. (c) 2007 Elsevier B.V. All rights reserved.

引用

页码：630 / 634

页数：5

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