Fabrication of TiNi alloy matrix composites with near-zero thermal expansion behavior and their properties

作者：Luo, Jun-Ping; Ma, Xiao; Guan, Rui-Feng; Cao, Shan-Shan; Ke, Chang-Bo; Ngai, Tung-Wai; Zhang, Xin-Ping^*

来源：Chinese Journal of Nonferrous Metals, 2014, 24(2): 461-467.

• Coefficients of thermal expansions
• Phase constituent
• Porous TiNi alloy
• Powder metallurgy process
• Pressureless infiltration technique
• Temperature range
• TiNi alloy
• Zero thermal expansion

TiNi alloy based composites tailored by Mg alloy (AZ91D) were fabricated by powder metallurgy process combining with pressureless infiltration technique, which possess low density, high strength and the near-zero thermal expansion performance. The results show that, the AZ91D/TiNi composites exhibit near-zero thermal expansion performance at a certain temperature range when the AZ91D alloy mass fraction is between 8.20% and 13.95%. The experimentally measured coefficients of thermal expansion (CTEs) of the composites are close to those theoretically ones predicted by the rule-of-mixture (ROM). It is proposed that the negative thermal expansion (NTE) phenomenon of the porous TiNi alloy originates from the volume change accompanying the phase transformations of the TiNi alloy matrix. The near-zero thermal expansion performance of AZ91D/TiNi composites is attributed to the combination of the NTE produced by the porous TiNi alloy matrix and the positive thermal expansion provided by the infiltrated AZ91D alloy phase. The introduction of AZ91D alloy has little influence on the phase constituents and transformation characteristics of the bulk matrix, while significantly increasing the strength of the composite. At the meantime, the steady linear superelasticity of the composites is maintained.

• 出版日期2014-2
• 单位华南理工大学