TGZM效应下Co-87.9%Sb合金糊状区的组织演化及成分变化

发布时间：2018-06-07 02:02

本文选题：TGZM效应 + Co-Sb合金　；参考：《稀有金属材料与工程》2017年10期

【摘要】：以TGZM(temperature gradient zone melting)效应为理论基础,将Co-87.9%Sb(质量分数,下同)合金置于定向凝固设备中加热熔化,在一定温度梯度下分别保温20 min,2 h,4 h后淬火,对其糊状区的凝固组织和成分分布进行了研究。结果表明:在一定温度梯度下,介乎于完全液相区和未熔固相区之间存在着固/液相共存的糊状区,Co-87.9%Sb合金的糊状区沿温度梯度方向分为CoSb_3+L,CoSb_2+L以及CoSb+L 3层;在TGZM效应作用下,随着保温时间的增加,糊状区内液相体积分数逐渐减少,糊状区与完全液相区界面向低温区移动;经保温处理后,由EDS获得的糊状区成分分布表明,糊状区内的溶质浓度明显偏离合金初始浓度,完全液相区溶质浓度高于初始值;通过理论分析与计算解释了上述现象。经过4 h保温处理后,糊状区CoSb_3+L部分中的CoSb_3含量大幅增加,在该部分高温端甚至可达98.8%,表明借助TGZM效应经过长时间保温制备CoSb_3热电材料的方法是可行的。
[Abstract]:On the basis of TGZM(temperature gradient zone melting) effect, Co-87.9 and SB alloy were heated and melted in a directional solidification equipment, and quenched after 20 min ~ 2 h ~ 4 h heat preservation at a certain temperature gradient, respectively. The solidification structure and composition distribution of the paste region were studied. The results show that at a certain temperature gradient, the paste zone of Co-87.9 SB alloy, which coexists between the complete liquid zone and the unmelted solid zone, is divided into CoSb_3 CoSb2L and CoSb L3 layers along the temperature gradient. With the increase of holding time, the volume fraction of liquid phase in the paste region decreases gradually, and the interface between the paste region and the complete liquid region moves to the low temperature zone. The solute concentration in the paste region deviates obviously from the initial concentration of the alloy, and the solute concentration in the complete liquid phase is higher than the initial value, which is explained by theoretical analysis and calculation. After 4 h heat preservation treatment, the content of CoSb_3 in the CoSb_3 L part of the paste region increased significantly, and even reached 98.8 at the high temperature end of the part, which indicated that it was feasible to prepare CoSb_3 thermoelectric material by using the TGZM effect for a long time.
【作者单位】：西北工业大学凝固技术国家重点实验室;
【基金】：陕西省自然科学基金(2015JM5149) 凝固技术国家重点实验室(西北工业大学)自主研究课题(101-QP-2014,133-QP-2015)
【分类号】：TB34;TG146.16

【相似文献】