Structure and properties of consolidated attrition-milled Al-5%Ti PM specimens

Mechanically alloyed aluminium-matrix composite powders have been prepared by 10 h attrition milling of Al-5wt%Ti in the presence of a wax. Different atmospheres have been used for the milling. Consolidation has been carried out by a double cycle of cold pressing and sintering, having obtained near full density samples. Powders contain up to 13vol% of Al3Ti reinforcing particles. In this paper the evolution of the specimens during the consolidation process is reported. Density and hardness are studied in the different stages during the double cold pressing and sintering process. The microstructural characteristics of final compacts is also studied as observed by optical and SEM microscopy, and XRD. Finally, tensile behaviour, as well as hardness, at room and high temperature, including fractographic characterization under SEM observation is reported. Depending on the process, these aluminium-matrix composites can show tensile strengths in excess of 500 MPa with axial elongations around 5%.