Slip Resistance of Ti-Based High-Temperature Shape Memory Alloys
Slip Resistance of Ti-Based High-Temperature Shape Memory Alloys
复制标题
DOI：
10.1007/s40830-015-0050-z
复制
发表时间：
2016-02
影响因子：
2.2
通讯作者：
A. Ojha;H. Sehitoglu
中科院分区：
文献类型：
--
作者：
A. Ojha;H. Sehitoglu
具有Nb、Zr和Ta合金取代的钛具有高的塑性滑动阻力和在bcc（β）向正交转变时的高转变应变。在目前的研究中，我们确定的临界解析剪切应力（CRSS）的滑移在钛合金的组成范围很宽的Nb，Ta和Zr。CRSS得到与建议Peierls-Nabarro形式主义纳入广义堆垛层错能垒的第一性原理密度泛函理论（DFT）计算得到的滑移配置文件。随着失稳能的增加，马氏体滑移的临界剪切应力从80 MPa线性增加到280 MPa。钽的添加在提高能量势垒方面是最有效的。我们还证明了β和晶体结构的晶格参数作为Nb，Ta和Zr添加量的函数的组成依赖性，与实验一致。使用晶格常数，在[011]极中的转变应变被确定为高达11%，并且其幅度主要随着Zr的添加而增加。
Titanium with Nb, Zr, and Ta alloying substitutions possesses high plastic slip resistance and high transformation strains upon bcc (β) to orthorhombictransformation. In the current study, we determine the critical resolved shear stress (CRSS) for slip in Ti alloyed for a wide composition range of Nb, Ta, and Zr. The CRSS is obtained with a proposed Peierls–Nabarro formalism incorporating the generalized stacking fault energy barrier profile for slip obtained from the first-principles Density Functional Theory (DFT) calculations. The CRSS for slip of the orthorhombic martensite increases from 80 to 280 MPa linearly with increasing unstable fault energy. The addition of tantalum is most effective in raising the energy barriers. We also demonstrate the composition dependence of the lattice parameters of bothβandcrystal structures as a function of Nb, Ta, and Zr additions showing agreement with experiments. Using the lattice constants, the transformation strain is determined as high as 11 % in the [011] pole and its magnitude increases mainly with Zr addition.