微重力条件下Cu-Zr共晶合金的液固相变研究

发布时间：2018-10-09 21:40

【摘要】：采用落管方法实现了液态Cu-10 wt.%Zr亚共晶、Cu-12.27 wt.%Zr共晶和Cu-15 wt.%Zr过共晶合金在微重力无容器条件下的快速共晶与枝晶生长.Cu-12.27 wt.%Zr共晶合金的凝固组织随液滴直径减小由层片规则共晶向不规则共晶转变,且层片间距减小;Cu-10 wt.%Zr亚共晶合金的初生(Cu)相随液滴直径减小由粗大树枝晶向棒状晶转变,且所占体积分数增加,部分区域形成花状凝固组织,(Cu)相枝晶辐射向外生长;Cu-15 wt.%Zr过共晶合金初生相则为金属间化合物Cu_9Zr_2相,呈条状生长,随液滴直径减小冷却速率增大,凝固组织由宏观弯曲生长向球状晶胞转变.理论计算表明,三个合金液固相变枝晶与共晶的生长均由溶质扩散控制.测定Cu-10 wt.%Zr亚共晶合金初生(Cu)相显微硬度随液滴直径减小而增大,三个合金的共晶相随合金初始成分增大而增大.
[Abstract]:The rapid eutectic and dendritic growth of liquid Cu-10 wt.%Zr hypoeutectic Cu-12.27 wt.%Zr eutectic and Cu-15 wt.%Zr hypereutectic alloy under the condition of microgravity without containers were realized by falling tube method. The solidification microstructure of the eutectic alloy. Cu-12.27 wt.%Zr eutectic alloy decreased with the drop diameter. Then eutectic to irregular eutectic transition, The primary (Cu) phase of Cu-10 wt.%Zr hypereutectic alloy changed from coarse dendrite to rod-like crystal with the decrease of droplet diameter, and the volume fraction increased. In some regions, the dendrite radiation of, (Cu) phase in flower-shaped solidified structure grows outwards, and the primary phase of Cu-15 wt.%Zr hypereutectic alloy is intermetallic compound Cu_9Zr_2 phase, which grows striped and increases with the decrease of droplet diameter. The solidification structure changed from macroscopic bending growth to spherulite cell. The theoretical calculation shows that the growth of dendrite and eutectic is controlled by solute diffusion. The microhardness of primary (Cu) phase of Cu-10 wt.%Zr hypoeutectic alloy increases with the decrease of droplet diameter, while the eutectic phase of three alloys increases with the increase of the initial composition of the alloy.
【作者单位】：西北工业大学应用物理系;
【基金】：国家自然科学基金(批准号:51474175,51522102) 陕西省工业科技攻关项目(批准号:2015GY138)资助的课题~~
【分类号】：TG146.11

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