【摘要】 水冷铜坩埚非自耗电极电弧炉熔炼出的钛合金试样沿径向方向晶体组织由激冷层的等轴晶与柱状晶混合转化为柱状晶、树枝晶一直到等轴晶。基于一维温度场方程,建立了实验条件下液固界面的温度梯度随时间的关系及温度梯度与凝固速度之商和时间的关系,利用这些关系结合固液界面稳定性动力学原理解释了径向上晶体组织变化的原因。不同位置上的硬度不同,结合相应位置上的单位面积上的晶界长度LA及单位体积内的界面积Sv,基于塑性变形理论进行了合理解释。更多还原

【Abstract】 The structures of Ti alloy melted by cold-Cu mold non-consumable-electrode arc furnace change from equiaxed structure in chill layer to columnar structure, dendritic structure and equiaxed structure along the radial direction in turn. Based on temperature epuation, the relation between temperature grads of liquid- solid interface and time, the relation between the ratio of temperature grads of liquid- solid interface to solidification velocity and time were established. Used these relations and liquid-solid interface stability dynamic, the structure change was explained. The hardness on different location were different, which can be explained by theory of plastic deformation combined with quantitative metallogenetic.更多还原