Differences in microstructure of Pd77.5Au6Si16.5 alloy solidified under microgravity and gravity conditions

Autor: R. P. Liu, Jianhua Zhao, Xiangyi Zhang, Wenkui Wang, Zhicheng Qin, Yingfan Xu, Duanwei He
Rok vydání: 1999
Předmět:
Zdroj: Science in China Series A: Mathematics. 42:74-79
ISSN: 1862-2763
1006-9283
Popis: The microstructure of Pd77.5Au6Si16.5alloy solidified both on board a Chinese Retrievable Satellite and on the earth is studied. Postmortem analyses of microstructure presented that the same types of phases, primary phase (Pd3Si) and eutectics (Pd3Si + Pd solid solution) were formed in both cases. But the phase morphologies were quite different. It was dendritic for the primary phase and lamellar for the eutectics under normal gravity condition. However, under microgravity condition the primary phase was granular and the eutectic was peculiar network. Detailed analysis showed that the differences in morphologies of the microstructure were due to the existence of gravity-induced buoyancy convection on the earth which increased the mass transport abilities and decreased the thickness of the solute boundary in front of the solid-liquid interface during solidification under normal gravity condition.
Databáze: OpenAIRE
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