Jitai NIU
,
Wei GUO
,
Qingchang MENG
,
Xinmei ZHANG
,
Xingqiu LIU
,
Guangtao ZHOU
材料科学技术（英）
The liquid-phase-impacting (LPI) diffusion welding mechanism and microstructure of welded joint of aluminum matrix composite SiCp/101A have been studied. It shows that by LPI diffusion welding, the interface state between SiC particle and matrix is prominent, the harmful microstructure or brittle phase can be restrained from the welded joint. Moreover, the density of dislocation in the matrix near the interface and in the matrix are all so higher than that of parent composite, the dislocation entwists each other intensively resulted in welding the composite successfully.
关键词:
Aluminum matrix composite
,
null
,
null
Jitai NIU
,
Zhonghong LAI
,
MuZhen WANG
,
Liming LIU
,
Lin WU
材料科学技术（英）
The effects of laser welding parameter on strength of welded joints were studied. The mechanism for loss of joint strength was analyzed. It was pointed out that an important factor affecting joint strength is the reaction between matrix and reinforced phase. On the basis of this, the concept of critical Si activity alpha ([si]min) was proposed. Using appropriate welding parameters and Si activity, high quality laser welded joints in an aluminum matrix composite SiCW/6061A1 can be successfully obtained.
关键词:
Jitai NIU
,
Lihong HAN
,
Chonghao WOO
材料科学技术（英）
Grain growth and grain boundary sliding are the two main superplastic deformation mechanisms. In the paper, simulation work is focused on the sliding of a Σ13 (111) symmetric twist coincidence grain boundary, a Σ13 (110) asymmetric tilt coincidence grain boundary, and a Σ3 (110) symmetric tilt coincidence grain boundary in Al, and the energies of grain boundary for each of equilibrium configurations are computed. An embedded atom method (EAM) potential was used to simulate the atomic interactions in a bicrystal containing more than 2000 atoms. At 0 K, the relationships between total potential energy and time steps for 3 (111) symmetric twist coincidence grain boundary and Σ3(110) symmetric tilt coincidence grain boundary during sliding at 2 m/s represent the periodic characteristic. However, the relationship between total potential energy and time steps for Σ13 (110) asymmetric tilt coincidence grain boundary represents the damp surge characteristic. It is found that grain boundary sliding for Σ3 (110) symmetric tilt coincidence grain boundary is coupled with apparent grain boundary migration.
关键词:
Aluminum
,
null
,
null
,
null
