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Abstract: The W–15wt.% Cu composite powders were synthesized by a sol–gel method combining with hydrogen reduction. X-ray diffraction patterns show that pure W and Cu phases were obtained at a reduction temperature of 750°C for 2h. The particle size of such powder is in the range from 100 to 400nm and in each particle the W and Cu phases are seemingly mixed homogeneously in the nanometer scale. The powders were microwave sintered for 25min at different temperatures of 1050, 1150 and 1200°C, respectively. The results show that W–15wt.% Cu samples microwave sintered at 1200°C exhibit a relative density higher than 97% and an average particle size of W as small as 600nm. The thermal conductivity and the Vickers microhardness of the sintered W–15wt.% Cu samples are in the range from 140 to 187W/mK and from 235 to 347HV, respectively. [Copyright &y& Elsevier]

Abstract: The W–Ni alloys with varying amount of Ni (0.1, 0.25, 0.5 and 1.0wt.%) were microwave sintered at 1450°C for different holding time 5, 15 and 30min, and their microstructure, grain size, relative density, thermal conductivity, and Vickers microhardness were characterized. Comparing to the addition of Fe and Cr, the Ni addition can greatly improve the relative density and maintain the high thermal conductivity of W at the same time. It was shown that the addition of 1.0wt.% Ni into W and microwave sintering at 1450°C for 5min would be the best conditions to obtain W–Ni alloys with a relative density close to 100% and an average grain size as small as 15μm. The Vickers microhardness and thermal conductivity of the sintered W–Ni samples range from 370 to 440 and from 90 to 130W/mK, respectively. [Copyright &y& Elsevier]