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Zr41.25Ti13.75Ni10Cu12.5Be22.5块体非晶合金在过冷液相区内的拉伸断裂行为与拉伸温度及应变速率有关.在室温 条件下拉伸表现为剪切带扩展形成脆性断裂,在断口表面层出现了大量放射状脉状纹络,断口表面层的绝热升温现象导致断裂层温 度超过了液相线温度,从而在断面上出现熔融状液滴.在玻璃化转变温度点,断裂模式依然为脆性断裂,韧窝状形貌及脉状纹络代 替了放射状的脉状纹络分布于断口表面,同时伴随有熔融状液滴.计算表明,断口表面层绝热升温温度依然高于液相线温度.在更 高温度或较低应变速率条件下,断裂方式转变为颈缩断裂模式,在颈缩点顶端依然存在脉状纹络,而未能观察到熔融状液滴.分析 表明,在较高温度或较低应变速率条件下,绝热升温对断裂层的影响非常微弱,断口表层的温度没有明显升高.
The tensile fracture behavior of Zr41.25Ti13.75Ni10Cu12.5Be22.5 bulk amorphous alloy in the supercooled liquid region is related to the stretching temperature and strain rate.The tensile behavior at room temperature is characterized by the extension of shear band to brittle fracture , A large number of radial vein-like veins appeared on the surface of the fracture.The adiabatic temperature rise of the fracture surface layer caused the temperature of the fracture layer to exceed the temperature of the liquidus, resulting in a molten droplet on the fracture surface. At the glass transition temperature, The model is still brittle fracture, dimple-like morphology and vein-like veins instead of radial vein-like distribution on the fracture surface, accompanied by molten droplets calculated that the fracture surface layer adiabatic warming temperature is still higher than the liquid The phase transition temperature.When the temperature is higher or the strain rate is lower, the fracture mode transforms to the necking mode, and there are still veins in the top of the necking point, but the molten droplets can not be observed.The analysis shows that, At higher or lower strain rates, the effect of adiabatic heating on the fracture zone is very weak, and the temperature at the fracture surface does not increase significantly.