ZrTiNiCuBe块体非晶合金剪切带内温升与断裂温升

Temperature rise in shear bands and fracture temperature rise of ZrTiNiCuBe bulk amorphous alloy

在室温环境下(25℃)对某ZrTiNiCuBe块体非晶合金材料进行不同应变率条件下的静态与动态压缩实验。并采用扫描电镜技术(SEM)对试样断口、侧面等进行表征,对比静、动态条件下的应力-应变曲线形貌的差异。结果表明:静态压缩时为剪切断裂,微观形貌上出现脉状花样与剪切带;剪切带诱发裂纹的形成,裂纹随着剪切带扩展。动态压缩时为脆性解理断裂,断面粗糙且发现大量熔滴;断口处出现解理台阶,塑性阶段出现明显的锯齿流变现象。从能量守恒定律出发,利用变形过程中弹性应变能的变化规律推测剪切变形区域内温升的变化规律,温升的变化规律揭示锯齿流变与试样的断裂机制。

The quasi-static and dynamic compression mechanical properties of the ZrTiNiCuBe bulk amorphous alloy were investigated under different strain rates at room temperature. The fracture and side face were characterized by the SEM technology. The results show that shear fracture happenswhen the alloyis quasi-static compressed,the microstructuresobservedarevein pattern and shear bands.The cracks are generated and propagated along the shear bands.The brittle cleavage fracture happenswhen the alloyis dynamic compressed, andtherough fracture surfaces containing large amount of liquid droplets are observed. The fracture exhibits thecleavage steps, andtheobvious serrated flow phenomenonappearsin the plastic deformation stage. In the point ofenergy conservation law, the temperature rise in shear bands is deduced based on the variation of elastic strain energy.The serrated flow and fracture mechanism of the ZrTiNiCuBe bulk amorphous alloywas revealed.