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| Heusler合金Fe2VAl的晶体结构与热电性能研究 |
| Crystal structure and thermoelectric properties of Heusler alloy Fe2VAl |
| 投稿时间：2018-12-21 |
| DOI： |
| 中文关键词: Heusler合金 Fe2VAl 热电性能 晶体结构 |
| 英文关键词: Heusler alloy Fe2VAl thermoelectric performance crystal structure |
| 基金项目:国家自然科学基金资助项目(11574242). |
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| 摘要点击次数: 3925 |
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| 中文摘要: |
| 采用真空电弧熔炼和放电等离子烧结技术制备了Full-Heusler合金Fe2VAl,利用XRD、XPS对合金的物相结构与成分进行表征,在300~800 K温度区间内测试了合金的Seebeck系数、电阻率、热导率等热电参数,并将实验结果与基于L21有序结构Fe2VAl合金的模拟计算值进行了比较。结果表明,实验所制的合金样品中Fe、Al、V原子比接近于2∶1∶1,基本满足Fe2VAl合金的成分配比；结合XRD衍射谱及10 K下合金的饱和磁矩可知,所制合金样品中除了完全有序的L21结构相外,还存在部分的B2相。另一方面,基于热电性能测试结果可知,所制Fe2VAl合金表现出典型的n型半导体特性,其Seebeck系数和电阻率随着温度的升高而降低,这与利用VASP和BoltzTraP软件包结合计算得到的L21结构Fe2VAl合金的热电参数随温度(300~800 K)的变化趋势相符合；合金的热导率随着温度的升高呈先降低后升高的趋势,在500 K附近具有极小值,而无量纲参数热电优值ZT在500 K附近达到最大值,约为0.052。 |
| 英文摘要: |
| The Full-Heusler alloy Fe2VAl was prepared by vacuum arc melting and spark plasma sintering approaches. By means of XRD and XPS, the phase structure and composition of the as-prepared alloy were characterized. The thermoelectric parameters including the Seebeck coefficient, resistivity and thermal conductivity were measured in the temperature range of 300~800 K, which were compared with those calculated based on the Fe2VAl alloy in L21 ordered structure. The results show that the atomic ratio of Fe, Al and V in the as-prepared alloy sample is close to 2∶1∶1, which basically satisfies the distribution ratio in Fe2VAl alloy. Aided by the XRD diffraction spectra and the saturation magnetic moment of the Fe2VAl alloy measured at 10 K, it can be known that in addition to the fully ordered L21 structure, a small portion of B2 structure is present in the alloy sample. Besides, the results of thermoelectric performance tests indicate that the as-prepared Fe2VAl alloy exhibits the typical characteristics of n-type semiconductor, and its Seebeck coefficient (absolute value) and resistivity decrease with the increase of temperature (300~800 K), which is in a good coincidence with the changing trend calculated by VASP and BoltzTraP software package; the thermal conductivity of the alloy first decreases and then increases with the increase of temperature, and has a minimum value around 500 K, while the dimensionless thermoelectric figure of merit ZT reaches a maximum of 0.052 at approx. 500 K. |
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