Z. Liu
,
W.M. Mao
金属学报(英文版)
The semi-solid slurry of A356 alloy, which is grain-refined by Al-Ti-B master alloy, is prepared by low superheat pouring and slightly electromagnetic stirring. The effects of grain-refine on the morphology and the grain size of the primary α phase in the slurry manufactured are researched. The results indicate that the slurry with particle-like and rosette-like primary α phases can be prepared by low superheat pouring and slightly electromagnetic stirring from liquid A356 alloy grain-refined, in which the pouring temperature can be suitably raised. Compared with the A356 samples without grain-refined, the grain size and particle morphology of primary α phase as well as the distribution of the grain with particle-like or rosette-like along radial in the ingot in A356 are markedly improved by grain-refined.
关键词:
semi-solid
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null
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null
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null
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null
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null
徐璟
,
赵新兵
,
朱铁军
,
何旭昭
材料科学与工程学报
doi:10.14136/j.cnki.issn 1673-2812.2017.02.001
SiGe合金热电材料作为一种传统的高温热电材料一直以来受到广泛关注.本研究通过B在球磨SiGe合金中的P型掺杂,有效增加了材料的载流子浓度,优化材料的电学性能.通过球磨降低材料的晶粒尺寸,增强晶界对声子的散射,降低材料的晶格热导率.另外,B掺杂使点缺陷散射和载流子-声子散射得到增强,材料的晶格热导率进一步降低.在室温时,Si0.Ge0.2B0.04的晶格热导率为～4Wm-1K-1.由于掺杂后电导率提高,热导率降低,因此热电优值zT得到了提高.在850K时,Si0.Ge0.2B0.04的最大热电优值为0.42,与Si0.Ge0.2B0.002的样品相比,其优值提高了2.5倍左右.
关键词:
热电材料
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SiGe合金
,
硼掺杂
,
晶粒优化
