Sin'ichi Towata1, Hajime Ikuno1 and Sen'ichi Yamada1
1Toyota Central Research & Development Labs., Inc. Aichi
Multifilament type silicon-carbide fiber-reinforced aluminum alloys with whiskers or particulates were prepared by the squeeze casting process. The effects of additions of whiskers or particulates on the microstructure, strength and transverse fracture behaviour of the composites were investigated.
The results obtained are as follows:
(1) For Al-4.5%Cu matrix composite, the large CuAl2 phase were observed around and among the fibers in the conventional fiber composite. In the whisker or particulate hybrid composites, Cu appeared to be segregated in the regions of whiskers or particulates. (2) Longitudinal flexural strength was improved by the additions of whiskers or particulates. (3) Transverse flexural strength was also improved by the additions of whiskers or particulates. Transverse flexural fracture occurred at the fiber-matrix interface for the conventional composites, but occurred in the matrix near the interface for the whisker or particulate hybrid composites. (4) Since the hybrid effect in the present study arose from the separation of continuous fibers, the matrix can easily infiltrate among the fibers. Also the growth of the brittle second phase of the Al-Cu alloy, CuAl2, is inhibited around and among the fibers by the additions of whiskers or particulates.
silicon-carbide fiber, whisker, particulate, hybrid composite, aluminum-nickel matrix, aluminum-copper matrix, microstructure, strength, transverse fracture behaviour
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