Zhiying CHEN and Jiaqans DING (Lab. on Non-linear Mechanics of Continuous Media
,
Institute of Mechanics
,
Chinese Academy of Sciences
,
Beijing 100080
,
China)(To whom correspondence should be addressed)
材料科学技术（英）
Molecular dynamics simulations are carried out in order to Study the atomic structure of crystalline component of nanocrystalline α-Fe when it is consolidated from small grains. A two-dimensional computational block is used to simulate the consolidation process. All the preset dislocations in the original grains glide out of them in the consolidation process, but new dislocations can generate when the grain size is large enough. It shows that dislocations exist in the consolidated material rather than in the original grains. Whether dislocations exist in the crystalline component of the resultant model nano-material depends upon grain size. The critical value of grain size for dislocation generation appears to be about 9 nm. This result agrees with experiments qualitatively.
关键词:
K. Zhang and G.N. Chen Materials Center
,
Institute of Mechanics
,
The Chinese Academy of Sciences
,
Beijing 100080
,
China
金属学报(英文版)
The present investigation is aimed to understand the microstructure evolution of SiC p/Al Si composites, i.e. particle distribution and matrix microstructure in laser processing. Microstructures of SiC p/A356 composite and the monolithic alloy are comparatively studied through laser remelting process. It is observed that the particle remains its original distribution after re solidification, indicating rejection of particles by rapid solidification interface does not occur. The presence of particles does not lead to any change in the phase constitution and phase morphology in the matrix, but instead result in a considerable change in growth direction of primary phase. The underlying mechanism is rationalized based on the interplay between the particles and solidification interface.
关键词:
composites
,
null
,
null
