Wenlong ZHANG
,
Dezun WANG
,
Zhongkai YAO
,
Mingyuan GU
材料科学技术（英）
A 15 vol. pct SiCCw/Al composite was fabricated by a squeeze cast route followed by hot extrusion in the extrusion ratio of 18:1 and cold rolling to 50%. Microstructural evolution in the cold rolled composite during annealing was studied using macrohardness measurement and transmission electron microscopy (TEM). It was found that, during cold rolling the plastic flow of the matrix was restricted by the whiskers around them along the rolling direction, which resulted in different microstructure from near whiskers to far away. The cold rolled composite exhibited different microstructural development on 1 h annealing at different temperatures. Under annealing at about 100℃, recovery reaction occurred obviously and the introduction of SiC whiskers resulted in enhanced recovery reaction. Under annealing above about 200℃, recrystallization (growth of nuclei by high-angle grain boundary migration) and extended recovery took place simultaneously. When annealing temperature was increased up to 500℃, recrystallization fully took place in the cold rolled microstructure. The starting temperature of recrystallization was about 200℃. Whiskers played a role in stimulating the nucleation of recrystallization.
关键词:
Metal matrix composites
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null
,
null
Z.G.Liu
,
B.Gabbitas
,
D.L.Zhang
,
J.Liang
,
W.Gao
材料科学技术（英）
The production and microstructural characterization of two types of ceramic particulate reinforced Ti matrix composites (TMCs): Ti-6Al-4V/10~vol. pct TiB and Ti(Al,O)/58 vol. pct Al2O3 were studied. The Ti-6Al-4V/10 vol. pct TiB composite with refined microstructure has been produced using a combination of high energy mechanical milling and hot isostatic pressing. The Ti(Al,O)/58 vol. pct Al2O3 in-situ composite powder has been produced using a novel powder processing process which involves high energy mechanical milling of a mixture of Al and TiO2 powders to produce an Al/TiO2 composite powder followed by thermal treatment of the composite powder. The Ti(Al,O)/58 vol. pct Al2O3 composite powder has been used to produce coatings. Selected mechanical properties of the Ti-6Al-4V/10 vol. pct TiB composite and the high temperature oxidation resistance have also been evaluated.
关键词:
Ti alloy
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null
,
null
,
null
