论文部分内容阅读
采用分离式霍普金森压杆,对TC18钛合金试样进行室温高应变率(103s-1)剪切试验,通过光学显微镜、扫描电镜及透射电镜观察绝热剪切带微结构,研究高应变率变形条件下TC18钛合金中所形成绝热剪切带的晶粒细化机制。TEM观察表明:绝热剪切带中晶粒细化是由3种机制共同作用的结果。第1种机制是由于变形晶粒中位错快速增殖、快速运动、塞积,塞积处产生巨大应力集中,导致形成裂纹并最终断裂形成细小晶粒;第2种机制为本研究提出的细小晶粒由拉长晶粒的“内颈缩”方式形成;第3种机制——细小晶粒由动态再结晶形成。
A high-strain rate (103s-1) shearing test was carried out on a TC18 titanium alloy specimen by using a split Hopkinson pressure bar. The microstructure of the adiabatic shear band was observed by optical microscope, scanning electron microscope and transmission electron microscope. Grain Refinement Mechanism of Adiabatic Shear Bands in TC18 Titanium Alloy under Deformation Condition. TEM observations show that grain refinement in the adiabatic shear band is the result of the combined action of three mechanisms. The first kind of mechanism is that the dislocations in the deformed grains rapidly proliferate, move rapidly, plug and accumulate large stress concentration at the plugging area, resulting in the formation of cracks and the final fracture to form fine grains. The second mechanism is the small The grains are formed by lengthening the “necks” of the grains; the third mechanism - the fine grains are formed by dynamic recrystallization.