Preparation of functionally graded materials by pulse current pressure sintering of ball milled Al-50 at% Ti powder

A functionally graded material (FGM) laminated with five layers composing of Al, Ti and Al3Ti phases was prepared from an equimolar mixture of Al and Ti powders by combination of ball milling and pulse current pressure sintering (PCPS) processes. The characteristics of the FGM are as follows. (1) The volume fraction of Al3Ti phase in the laminated layers increases with increasing milling period of Al-50 at%Ti mixed powder. This results from the accelerated formation of Al3Ti in the PCPS process due to refinement of Al and Ti composite particles during milling. (2) The average value of Vickers hardness for each laminated layer of the FGM increases with increasing content of Al3Ti phase in the layer. The average hardness values of the five layers are 28, 165, 258, 425 and 520 HV, respectively.