Effect of copper infiltration and cooling rate on porosity and mechanical properties of Astaloy Mo sintered parts

Applications of Powder Metallurgy (PM) are expanding in automotive industry, aerospace and other engineering areas. The need for increasing the strength of components produced by PM has created different methods to consolidate these materials. Infiltration of metals with low melting temperature and heat treatment are the two main techniques for compensating the reduction of strength and hardness in PM components due to their porous structure. On this project, size and shape of pores after and before infiltration of copper (Cu) and its effect on hardness of PM parts produced by Astaloy Mo powder has been studied. Moreover, a comparison between the effect of cooling rate and infiltration on hardness of components has been performed. As the method of infiltration varied from one-step infiltration, when the ferrous compact is in the green condition to two-step infiltration, when the compact is in the sintered condition, mechanical properties of materials change significantly. Final microstructure and hardness of materials have been investigated by Scanning Electron Microscope and Light Optical Microscope and Vickers hardness test method and different methods for producing Astaloy Mo sintered parts have been compared with eachother.