Ke LI
,
Jun WANG
,
Da SHU
,
Baode SUN
,
Yaohe ZHOU
材料科学技术（英）
Cylinder-like in-situ Al/24Si FGMs were produced by using electromagnetic separating process. Si primary phase reinforced layer with volume fraction as high as 16 pct was formed at the outer region of the cylinder-like samples where the local hardness and wear resistance were enhanced remarkably. Moreover, both of strength and ductility in the inner region provided insurance of reliable strength for this as-cast gradient material. It indicated that general mechanical properties such as good wear resistance at the outer region and good ductility in the central part could be obtained with the optimized redistribution of the Si primary particles under the electromagnetic force.
关键词:
FGMs
,
null
,
null
Jun WANG
,
Shuxian HE
,
Baode SUN
,
Yaohe ZHOU
材料科学技术（英）
To increase the casting quality of hypoeutectic Al-Si alloys, the effects of melt thermal treatment on the solidification structure of the A356 alloy were analyzed by a factorial experiment, in which the overheated melt was mixed with the low temperature melt. Experimental results show that the elongation ratio and strength of the treated samples increase remarkably compared with the control sample. The primary dendrite size reduces dramatically and the dendrite changes from columnar to equiaxed, with a little change of the secondary dendrite arm spacing (SDAS). Combined with the measurement of the nucleation undercooling, it is concluded that the solidification structure and refining effect are dependent primarily on the low temperature melt. The refining mechanism is believed as a result of the multiplication of the nuclei in the melt thermal treatment procedure
关键词:
A356
,
null
,
null
Tianxiao LI
,
Zhenming XU
,
Baode SUN
,
Da SHU
,
Yaohe ZHOU
材料科学技术（英）
Physical simulation is used to study the movement of nonmetallic particles in Al melt in electromagnetic field. It is found that the terminal velocity of particles in different Reynolds number range has different functions. By confirming drag force coefficient of nonmetallic particles with Reynolds number in the range of 0.2 similar to 10 and 10 similar to 25 respectively, two functions of terminal velocity for spherical nonmetallic particles have been got accordingly, which provide a theoretical basis for separating nonmetallic inclusions from Al melt in electromagnetic field.
关键词:
