高应变速率下钛-钢复合板界面组织特征及变形机制

在高应变速率下,钛-钢复合板不同材料以不同的变形机制协调变形,结合界面起到至关重要的作用.本文分析研究了高应变速率下钛-钢复合板的界面组织特征和变形机制.结果表明:在钢侧,随着应变速率的提高,小角度(3°~10°)晶界含量增多,织构组分{1-12}〈2-41〉逐渐演变为织构{6-65}〈38-6〉和{111}〈1-10〉.在钛侧,随着应变速率的提高,出现了明显的形变孪晶组织,三种形变孪晶如{11-21}〈1-100〉拉伸孪晶、{11-22}〈11-23〉压缩孪晶和{10-12}〈10-11〉拉伸孪晶产生的难易程度不一样,变形机制由常规的"孪生变形为主"转变为"位错滑移与孪生变形共存"的复合变形模式.在结合界面处,随着应变速率的提高,需要适应由两侧产生的不同变形抗力,才能够实现连续变形而不致使材料发生破坏,其主要的协调机制依靠结合界面及附近晶粒的滑移实现变形.

Interfacial microstructure and deformation mechanism of Ti-steel clad plate under high strain rate

Under high-strain-rate conditions, Ti and steel in Ti-steel clad plate deformed, with the deformation compatibility mechanism playing a key role at the bonding interface.The interfacial microstructure and deformation mechanism of Ti-steel clad plate under high strain were investigated in this paper.The results show that, for the steel side, with increasing strain rate, the number of small-angle (3°-10°) grain boundaries increases and texture component {1-12}〈2-41〉 gradually evolves into textures {6-65}〈38-6〉 and {111}〈1-10〉.For the Ti side, with increasing strain rate, deformation twins appear.Different deformation twins such as tensile twin {11-21}〈1-100〉, compression twin {11-22}〈11-23〉, and tensile twin {10-12}〈10-11〉 are produced.The deformation mechanism of the Ti side at high strain rate transforms from a conventional "twin deformation" mode to the compound deformation mode "coexistence of dislocation slip and twin deformation." With the increase of strain rate, the bonding interface would coordinate the different deformation resistances of both sides, to achieve a continuous deformation without any materials damage.The main coordination mechanism relies on the bonding interface and the slip of adjacent grains.