Mohammed, Kahtan S.
(2010)
Study Of The Effect Of Sintering Parameters On
Characteristics Of W-Bronze Composites Prepared Via
Different Densification Techniques.
PhD thesis, Universiti Sains Malaysia.
Abstract
W-bronze composites are very promising MMC material. It has high potential
in military and industrial applications and it can replace lead in different fields where
the density is of main consideration. In this study, since tungsten metal and bronze
alloy are almost completely immiscible in both solid and liquid phases, different
approaches and techniques were utilized to attain highly dense and homogenously
structured composites. Super-solidus liquid phase sintering with 2 to 3 wt.% Fe
additions improved the hardness by two folds and the sintered density by 5 % to
10%. Mechanical alloying of the W, Cu and Sn powder precursors by two-step
process yielded composite particles of W impregnated in Cu-Sn matrix. The outcome
after sintering was a composite of 85 to 95% of their theoretical density with
excellent corrosion and wear resistance properties. By the implementation of a
proposed new shell-on-core densification technique, composites of different
compositions with 95-99% of their theoretical density were attained. The different
W-bronze composite materials produced, were subjected to different laboratory
testing and examinations to assess their microstructural, fractural, mechanical,
chemical and physical properties.
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