Superplasticity of Ti2448 alloy with nanostructured grains
Superplasticity of Ti2448 alloy with nanostructured grains
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DOI：
10.1016/s1005-0302(12)60003-6
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发表时间：
2011-12
影响因子：
10.9
通讯作者：
M. Xiao;Yingxuan Tian;G. Mao;Shumu Li;Y. Hao;R. Yang
中科院分区：
文献类型：
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作者：
M. Xiao;Yingxuan Tian;G. Mao;Shumu Li;Y. Hao;R. Yang
Ti-24 Nb-4 Zr-8 Sn（根据其化学成分的重量百分比缩写为Ti 2448）是具有体心立方（bcc）晶体结构的多功能β型钛合金，其高度局部化的塑性变形行为在常规冷加工过程中显著有助于晶粒细化。本文采用冷轧法制备了晶粒尺寸小于50 nm的纳米结构（NS）合金，通过单轴拉伸实验研究了其在初始应变速率为1.5×10−2、1.5×10− 3和1.6×10−4s− 1，温度为600、650和700°C下的超塑性变形行为。结果表明，与50 μm的粗晶合金相比，NS合金具有更好的超塑性，延伸率可达275%以上，抗拉强度可达50-100 MPa。NS合金在600、650和700°C下的应变速率敏感性（m）分别为0.21、0.30和0.29。结果表明，晶粒细化是提高Ti 2448合金超塑性的有效途径。
Ti-24Nb-4Zr-8Sn, abbreviated as Ti2448 from its chemical composition in weight percent, is a multifunctional β type titanium alloy with body centered cubic (bcc) crystal structure, and its highly localized plastic deformation behavior contributes significantly to grain refinement during conventional cold processing. In the paper, the nanostructured (NS) alloy with grain size less than 50 nm produced by cold rolling has been used to investigate its superplastic deformation behavior by uniaxial tensile tests at initial strain rates of 1.5×10−2, 1.5×10−3and 1.6×10−4s−1and temperatures of 600, 650 and 700°C. The results show that, in comparison with the coarse-grained alloy with size of 50 μm, the NS alloy has better superplasticity with elongation up to ∼275% and ultimate strength of 50-100 MPa. Strain rate sensitivity (m) of the NS alloy is 0.21, 0.30 and 0.29 for 600, 650 and 700°C, respectively. These results demonstrate that grain refinement is a valid way to enhance the superplasticity of Ti2448 alloy.