【摘要】 采用光学显微镜和热场发射高分辨率电镜对厚度为0.2 mm交叉轧制钼带及其冷拉深成形和高应变速率激光冲击成形试件的微观组织及显微裂纹进行观察和分析。结果表明:交叉轧制钼带由排列紧凑相互搭接的纤维状细长晶粒组成,拉伸断口呈薄层韧性断裂且晶内显微裂纹相互搭接;多晶钼带内部产生的显微裂纹均发生在晶间结合较弱的厚度方向中间区域,沿纤维晶界且相互搭接,仅在内部产生的拉应力大于弱界面结合强度时,弱界面将产生显微裂纹。更多还原

【Abstract】 Using optical microscopy and field emission high-resolution electron microscopy,the microstructure and micro-cracks of the 0.2 mm thick cross-rolled molybdenum strip,its cold deep drawing parts and laser shock forming parts under high strain rate were observed and analyzed.The results showed that the cross-rolled molybdenum strip was composed with mutual overlapping and compact slender fibrous grains.Tensile fracture exhibited thin layers of ductile fracture and microcracks overlapping each other within the fibrous grains of polycrystalline molybdenum strip.And the microcracks appeared in the middle region of the thickness direction where intergranular combination was weak.Only when internal tensile stress was greater than the bonding strength of weak interface,microcracks were generated on the weak interface.更多还原