L.H. Han
,
J.T. Niu
,
D.M. Jiang
金属学报(英文版)
The superplasticity of AlNp/6061Al composite, fabricated by powder metallurgy method and hot-rolled after extrusion, was investigated. The AlNp/6061Al composite exhibits an m-value of 0.49 and a maximum elongation of 438% in the strain rates ranging from 10-2-10°s-1 and at temperatures from 823K to 893K. Differential scanning calorimeter was used to ascertain the possibility of any partial melting in the vicinity of optimum superplastic temperature. These results suggested that liquid phase existed where maximum elongation was obtained.
关键词:
superplasticity
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null
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W. Guo
,
J.T. Niu
,
J.F. Zhai
金属学报(英文版)
Non-interlayer liquid phase dissusion welding (China Patent) and laser welding methods for aluminum matrix composite are mainly described in this paper. In the noninterlayer liquid phase dissusion welding, the key processing parameters affecting the strength of joint is welding temperature. When temperature rises beyond solidus tem perature, the bonded line vanishes. The strength of joint reaches the maximum and becomes constant when welding temperature is close to liquid phase temperature. Ox- ide lm in the interface is no longer detected by SEM in the welded joint. With this kind of technique, particle reinforced aluminum matrix composite Al2O3p/6061Al is welded successfully, and the joint strength is about 80% of the strength of composite (as-casted). In the laser welding, results indicate that because of the huge speci c surface area of the reinforcement, the interfacial reaction between the matrix and the reinforcement is restrained intensively at certain laser power and pulsed laser beam. The laser pulse frequency directly affects the reinforcement segregation and the rein- forcement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. The maximum strength of the weld can reach 70% of the strength of the parent.
关键词:
non-interlayer liquid phase dissusion welding
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