The Effect of the Green Density on the Properties of Powder Metallurgy Ti Sintered by High Frequency Induction Heating

Abstract

Sintering is a vital technology used for consolidation of metal and ceramic powders. The process is generally long and energy consuming because of the way in which heat transfer happens in electrical and gas furnaces. This study focuses on optimizing the sintering process of metallic powders, in particular titanium, using high frequency induction heating as alternative sintering method. Using electromagnetic induction and the associated Eddy current effect, the heat is generated directly into the electrically conductive object. Consequently, faster heating rates and lower heat loses are achieved. The purpose of this study is to understand the effect of process parameters, such as the powder compact density, on the efficiency of the induction heating and the properties of the sintered materials. The average heating rates recorded while heating to 1300oC are in the range of 3.5o to 15.3o C per second. Significant densification and consolidation, evident by the amount of closed porosity and increase in tensile strength was found in spite of the short heating time. The results show that the powder compact density plays a crucial role on the heating efficiency as well on the properties of the sintered material such as final density, porosity distribution and tensile properties. The samples with higher initial density showed tensile strength and ductility values comparable to those of high vacuum sintered and those specified by international standards for powder metallurgy Ti products.