| Abstract: |
Plasma spray forming is recently explored as a near-net-shape fabrication route for ultra-high temperature metals and ceramics. In this study, monolithic tungsten and its composite have been produced using an atmospheric plasma spraying and subsequent high temperature sintering. The sprayformed tungsten-based preforms from different processing parameters have been evaluated for their metallurgical aspects, such as density, oxygen content and hardness. A well-defined lamellae structure was formed in the deposit by spreading of completely molten droplets, with incorporating small amounts of unmelted/partially-melted particles. Plasma sprayed tungsten deposit had 84-87% theoretical density and 0.2-0.3wt.% oxygen content. Subsequent sintering at elevated temperatures promoted the formation of equiaxed grain structure and the production of dense preform up to 98% theoretical density. Addition of small amounts of ZrC particles led to an increase in hardness in the deposit, and would improve mechanical properties of tungsten based preform.
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