Mg-Y-Nd-Zr合金的高温变形行为与热加工性能

HOT DEFORMATION BEHAVIOR AND HOT WORKABILITY OF Mg-Y-Nd-Zr ALLOY

研究了一种Mg-Y-Nd-Zr合金在300—500℃和应变速率为0．001—1s^(-1)条件下的高温变形行为．利用动态材料模型构建了热加工图,结合组织观察结果认为,该合金在450—500℃、应变速率约为0．01s^(-1)条件下发生动态再结晶；而温度高于450℃、应变速率约为0．005s^(-1)时,材料发生晶界开裂；温度低于350℃、应变速率约为0．01s^(-1)时,材料在变形过程中由于机械孪生导致开裂；温度为450℃左右、应变速率高于0．5s^(-1)时,材料在变形过程中发生剪切开裂．

The deformation behaviors of a kind of Mg-Y-Nd-Zr alloy at temperature range of 300--500 ℃ and strain rate range of 0.001-1 s^-1 have been studied by compressive tests. Processing map of this alloy was established on the basis of dynamic material model. Microstructure observations suggested that the processing map could be characterized by four domains： dynamic recrystallization domain at 450--500 ℃ and about 0.01 s^-1; grain boundary cracking domain at temperatures higher than 450 ℃ and strain rates of about 0.005 s^-1; flow instability domain due to mechanical twinning at temperature below 350 ℃ and strain rate of about 0.01 s^-1; shearing fracture at about 450 ℃ and strain rates above 0.5 s^-1.