Zheng LIU
金属学报(英文版)
doi:10.1016/S1006-7191(08)60118-0
Semi-solid slurry of A356 alloy was prepared by low superheat pouring and slightly electromagnetic stirring, and the fractal characteristics of morphology in semi-solid primary phase was researched. The fractal dimensions of primary phase morphology in the semi-solid A356 alloy were calculated by the program written to calculate the fractal dimensions of box-counting in the image of solid phase morphology in semi-solid metal slurry. The results indicated that the morphology of primary phase in semi-solid A356 prepared by low superheat pouring and slightly electromagnetic stirring is characterized by fractal dimension, and the primary phase morphology obtained by the different processing parameters has different fractal dimensions. The morphology of primary phase at the different position of ingot has different fractal dimensions, which reflected the effect of solidified conditions at different positions in the same ingot on the morphology of semi-solid primary phase. Solidification of semi-solid alloy is a course of change in fractal dimension.
关键词:
Semi-solid
,
初生相形貌
,
分形
,
A356铝合金 semi-solid, morphology of primary phase, fractal, A356 alloy
Zheng LIU
金属学报(英文版)
Semi-solid Al7Si0.3Mg alloy slurry, which is grain-refined by yttrium, is manufactured by low temperature pouring. The effects of grain-refined by yttrium on the morphology and the grain size of the primary α-Al in semi-solid Al7Si0.3Mg alloy are researched. The results indicate that semi-solid Al7Si0.3Mg alloy with particle-like and rosette-like primary α-Al can be prepared by low temperature pouring from liquid Al7Si0.3Mg alloy grain-refined by yttrium. The grain size and particle morphology of primary α-Al in Al7Si0.3Mg alloy are markedly improved by 0.5 wt pct Y. The refining mechanism of Y on the morphology and the grain size of the primary $\alpha$-Al in semi-solid Al7Si0.3Mg alloy are delved.
关键词:
Semi-solid
,
钇
,
Al7Si0.3Mg合金
,
细化机制
Zheng LIU
,
Ligang WANG
,
Lai WANG
材料科学技术（英文）
The microstructures, the changing rule of carbon-enriched zone, the diffusion behaviors of elements C and Cr, and the carbide type of 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints after aging at 500℃ for various times and after long-term service in technical practice were investigated by using the optical microscopy, electron probe microanalysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that in aging 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints, the main carbides are M3C and a few carbides are M7C3 and M23C6. The M3C carbide decomposition and dissolution with increasing aging time or aging temperature and the anti-diffusion of C and Cr cause the decrease and disappearance of the carbon-enriched zone. The results are different from those of the A302/1Cr5Mo dissimilar welded joints in previous studies.
关键词:
Dissimilar welded joint
,
null
,
null
,
null
