Jia ZHANG
,
Keqiang QIU
,
Aimin WANG
,
Haifeng ZHANG
,
Mingxiu QUAN
,
Zhuangqi HU
材料科学技术（英）
The Mg65Cu25Y10 melts were quenched at a temperature of 973 K under various pressures in the range of 2～5 GPa and ambient pressure. The microstructure of the solidified specimens has been investigated by X-ray diffraction, transmission electron microscope and electron probe microanalysis. Experimental results show that the pressure has a great influence on the solidification microstructure of the Mg65Cu25Y10. At ambient pressure, the solidification products are Mg2(Cu,Y) and a very small amount of Y2O3 inclusion. As the pressure is above 2 GPa, a new Cu2(Y,Mg) phase appears, while Y2O3 is not observed at the pressure of 3, 4 and 5 GPa. When the pressure increases from 2 GPa to 5 GPa, the grain sizes of Mg2(Cu,Y) and Cu2(Y,Mg) decrease from 125, 96 nm to 80, 7 nm, respectively. The mechanisms for the effects of the pressure on the phase evolution and microstructure during solidification process of Mg65Cu25Y10 alloy have been discussed.
关键词:
Mg65Cu25Y10 alloy
,
null
,
null
Xianfeng PAN
,
Haifeng ZHANG
,
Aimin WANG
,
Bingzhe DING
,
Keqiang QIU
,
Zhuangqi HU
材料科学技术（英）
This paper reviewed the trend and development of semi-solid metal technique. The processes and mechanisms for producing slurry of SSM and its industrial applications have been summarized and discussed. Discussions on the basic rheological theory are presented for more applications. Further consideration of the development and application of SSM technique is also proposed.
关键词:
Jianjun LIU
,
Keqiang QIU
,
Aimin WANG
,
Haifeng ZHANG
,
Bingzhe DING
,
Zhuangqi HU
材料科学技术（英）
The effect of pressure on the variation of the crystallization phases of the Zr55Cu30Al10Ni5 bulk glass and its thermal stability under high pressure annealing was investigated by X-ray diffraction (XRD) and differential scanning calorimeter (DSC). The mode of crystallization and products of crystallization of the Zr55Cu30Al10Ni5 bulk glass were quite different under different pressure. At ambient pressure, the crystallization products consisted of NiZr2 and CuZr2, while at pressure of 1 GPa and 3 GPa, the alloys crystallized into NiZr2 and Cu10Zr7, respectively. The alloy was nearly not crystallized and only a small amount of Cu10Zr7 was precipitated under 5 GPa. DSC proved that the mode of the crystallization under high pressure was different from that at ambient pressure.
关键词:
Bulk metallic glan
,
null
,
null
桂南
,
樊建人
,
陈松
工程热物理学报
本文采用直接数值模拟计算了Re=669,S=1.42强旋流中的颗粒运动特性.计算的部分流动条件依照SommerfeId & Qiu的实验条件进行模化.模拟的结果揭示了旋流近场的颗粒运动的浓度、速度的时均量和脉动值的统计分布特性.
关键词:
旋流
,
颗粒运动
,
直接数值模拟
,
统计特性
