李鑫,谢辉,张亚龙,魏鑫.定向凝固Mg2Si1-xSnx合金功率因子优化和热电性能研究[J].稀有金属材料与工程,2020,49(8):2779~2785.[Li Xin,Xie Hui,Zhang Yalong,Wei Xin.Power Factor Optimization and Thermoelectric Properties of Mg2Si1-xSnx Alloys by Directional Solidification[J].Rare Metal Materials and Engineering,2020,49(8):2779~2785.]
定向凝固Mg2Si1-xSnx合金功率因子优化和热电性能研究
投稿时间:2019-12-27  修订日期:2020-03-02
中文关键词:  晶体生长  定向凝固  功率因子  Mg[sub_s]2[sub_e]Si[sub_s]1-x[sub_e]Sn[sub_s]x[sub_e]
基金项目:国家自然科学基金青年项目(项目号:51904219); 西安航空学院校级科研资(项目号:2019KY0203)
中文摘要:
      通过高温度梯度定向凝固方法制备了高质量的Mg2Si1-xSnx晶体,对1.5at%Bi掺杂条件下不同Sn含量的合金进行了热电性能测试和电子传输性能的第一性原理计算。x=0.625时,由于达到能带收敛条件,Seebeck系数和功率因子均达到最大值,测试结果分别为-247μVK-1和5.7mWm-1K-2,与计算预测结果一致,与纳米级晶粒的块体材料相比,功率因子提升了25%。在T=700K处计算预测的最大ZT值为1.3,而实验测试值为1.16,而且在中温区的550K到800K之间预测和实验测试的ZT值均可以保持在0.9以上。通过优化功率因子的方法可以有效提高Mg2Si1-xSnx晶体的热电性能,而且可以避免热电器件在高温环境长时间服役时,由于晶粒长大而导致的性能降低。
Power Factor Optimization and Thermoelectric Properties of Mg2Si1-xSnx Alloys by Directional Solidification
英文关键词:crystal growth  directional solidification  power factor  Mg2Si1-xSnx
英文摘要:
      Single-phase Mg2Si1-xSnx crystal was successfully directionally solidified from the melt. Thermoelectric properties were tested for 1.5at%Bi-doped crystals with different Sn contents, and electronic transport properties were predicted by the first-principle calculation. At x=0.625, tested Seebeck coefficient and power factor is -247μVK-1 and 5.7mWm-1K-2, respectively, because the band structure of Mg2Si0.375Sn0.625 is converged. This result is consistent with the calculated values, and the power factor enhanced 25%. The predicted and tested results of ZT maximum are 1.3 and 1.16 at T=700K, respectively. In the medium temperature range of 550K-800K, the predicted and tested ZT values can keep above 0.9. Power factor optimization is an effective way to improve the thermoelectric properties of Mg2Si1-xSnx crystal. In addition, the performance deterioration of thermoelectric devices induced by nano-sized grain growth at high service temperature can be avoided.
作者单位E-mail
李鑫 西安航空学院 lixin005@xaau.edu.cn 
谢辉 西安航空学院  
张亚龙 西安航空学院  
魏鑫 西安航空学院  
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