The quantitative understanding on the influence of α″ phase on mechanical behavior of Ti-Nb-Ta-Zr-O alloy

In this paper, the influence of β→α′′ phase transformation, considering the effects of nanoclusters and other factors, on the mechanical properties of TNTZO titanium alloy at nanoscale and low strain are studied. A dislocation based model is set to understand how microstructures inside like twins, nanoclusters and martensite affect the total performance of the alloys. According to different distribution of these microstructures, two types of grains are assumed to construct the representative volume element. Then, the comparison between calculated result (Young's modulus E: 65 GPa-75 GPa) and experiment data (E = 69 GPa) [1] proves the accuracy of the theoretical model. And the results show that martensite accounts for a large contribution to total stress level and increasing the content of martensite can effectively improve the mechanical properties of the material, but this rising rate will gradually decrease. Also, improving content of nanocluster can lead to similar result. The presence of nanoclusters inhibits the growth of martensite and reduces the content of martensite. However, reducing the content of martensite and appropriately increasing the nanocluster content can reduce the modulus of elasticity while maintaining a certain stress level.