TITLE:
Synthesis and Densification of Tungsten-Brass Composite by Mechanical Alloying
AUTHORS:
Kahtan S. Mohammed, Baba Gowon, Shamsul Baharin Bin Jamaluddin, Zuhailawati Hussain, Polycarp Evarastics
KEYWORDS:
W-Brass, Mechanical Alloying, Microstructure, Expansion, Hardness
JOURNAL NAME:
Open Journal of Metal,
Vol.5 No.3,
September
1,
2015
ABSTRACT: Fabrication of full-density W-brass composites is very difficult to achieve because of evaporation
of zinc, insolubility of W and brass and compacts expansion. In this study, to achieve full-density
W-brass composites, mechanical alloying (MA) and activated sintering process were utilized. Mechanical
coating of W with Ni using high energy planetary ball mill was carried out. The milling
was divided into two stages: to alloy and modify the surface of W with Ni for enhanced activation.
The microstructure of the milled powders and sintered compacts, elemental composition and
phases present were studied by using scanning electron microscopy (SEM), energy dispersive
X-ray spectroscopy (EDX) and X-ray diffraction (XRD) respectively. As-received powder compacts
was also sintered under the same condition for comparison purpose. The effects of milling time on
the microstructure, sinterability and the hardness of the composites were investigated. It was observed
that the samples produced from 8 h milled powder had the highest relative sintered density
(98% TD) and microhardness (234 Hv). On the other hand, the samples from the as-received
powders expanded and had a relative sintered density of (67% TD) and microhardness as low as
24 Hv. The significance of this study is the possibility of producing W-brass composites as a
cheaper alternative to W-Cu composites.