Papers by Author: Jun Wang

Abstract: Warm flow compaction is a new, simple and economy process that can produce complex powder metallurgy parts. A special apparatus for measuring the lateral flow capability of the powder was designed and manufactured. It can be used to analyze the feasibility of forming complex cross-shaped parts. The preparation of the powder blend and effects of pressing speed, temperature and axial pressure on the lateral flow capability of a tungsten-base powder mix were investigated. Results showed that the lateral-pressure increased with increased pressing speed and increased applied axial-pressure. The lateral-pressure decreased as lateral-distance increased. Biggest lateral-pressure was obtained when the powder blend was pressed at around 96 °C, at which the binder start to melt. In this study cross-shaped powder metallurgy parts were successfully prepared by warm flow compaction.

Abstract: Warm compacting and sintering behaviors of pre-mixed Fe-2Ni-2Cu-1Mo-1C powders were studied. Results showed that green density increased with compacting temperature and then fell slightly; the maximum green density was obtained at about 120°C. Green compact density and spring back effect of the pre-mixed powder increased gradually as the compacting pressure increased. Sintered density first increased and then fell as the temperatures went up under different sintering temperatures for 50 minutes, but the trends of sintering dilatation were first reduced and then increased. Sintered density first reduced and then increased with the prolonged sintering time at 1300°C, but the trends of dimension change after sintering were the very reverse. Tensile strength, elongation and hardness of the warm compacted Fe-2Ni-2Cu-1Mo-1C materials generally increased as sintering temperature and sintering time went up.