Age Hardening and Its Modeling of Ti-10Mo-8V-1Fe-3.5Al Alloy

摘要:

对Ti-10Mo-8V-1Fe-3.5Al (TB3)合金时效强化过程及时效强化机制进行了详细研究。对时效后经过塑性变形的TB3样品进行透射电子显微镜（TEM）观察发现：在早期时效样品中，位错可以绕过细小的α片；而在时效后期的样品中，α片尺寸长大且伴随着体积分数增大，β晶粒被粗大的α片分割成许多封闭的单元，变形过程中位错不能绕过这些粗大的α片而被限制在这些相对封闭的单元中。鉴于此，对早期时效（时效时间少于2 h）的TB3合金，结合Orowan强化机制及强度混合定律建立了其时效强度模型，而对于时效后期（时效时间超过2 h）试样，结合细晶强化理论及强度混合定律建立了时效强度模型。这些强度模型的计算结果与实测值吻合

Abstract:

The age hardening behavior and the relevant strengthening mechanisms of Ti-10Mo-8V-1Fe-3.5Al (TB3) alloy have been investigated. A transmission electron microscope (TEM) was used to investigate the microstructures of aged and deformed TB3 specimens. It can be observed that dislocations can bypass the small α platelets in early aged samples. However, in late aged samples. the precipitated α platelets are large with high volume fraction, so that the β grains are divided into isolated β cells. In other words, the β grains are heavily refined. During plastic deformation, the dislocations generated in these β cells can not bypass the large α platelets by Orowan mechanism, but are confined within them. The strength model of the early aged TB3 alloy (aging time less than 2 h) is established by combining the law of mixtures with Orowan strengthening theory. For late aged TB3 alloy (aging time longer than 2 h), the strength model is established by combining the law of mixtures with fine grain strengthening theory. The predicated yield strength according to the modified strength models above can meet well with the measured values