THE EFFECT OF COBALT ADDITIVE ON MICROSTRUCTURE AND PROPERTIES OF W-CU COMPOSITES PREPARED BY SINTERING AND INFILTRATION PROCESSES

In the present paper, the influence of cobalt additive on the sintering/infiltration behavior of w-cu compositewas studied. for this purpose, the mixed powders of tungsten and cobalt were compacted by cip method and thensintered at 1450, 1550 and 1600 °c in a hydrogen atmosphere. the sintered specimens at 1550 °c were subsequentlyinfiltrated with liquid copper at 1250 °c for 10, 60 and 120 min. the microstructure and composition of samples wereevaluated using sem, eds as well as xrd techniques. the density of the sintered samples was measured byarchimedes method. vickers indentation test was used to measurement hardness. it was found that sinteringmechanism of tungsten powder depends on temperature and cobalt additive content. also, the best infiltration behaviorwas observed in the samples with optimum cobalt value. in addition, it was found that the w-w contiguity as well asdihedral angle decreases as cobalt increases. density and hardness of infiltrated specimens are attained 16.28-16.79g.cm-3 and 220-251 vhn, respectively.