Elemental blended powders semisolid forming of Ti-Al based alloys

Abstract

Ti-6Al and Ti-6Al-4V alloys fabricated by semisolid forming are investigated with microscopic observation, density measurements, X-ray diffraction and mechanical property tests. The effects of the forming pressure, the forming temperature, and the forming loading time on the density of the green compacts are discussed. The shaped green-compact that is prepared by semisolid forming method transforms into intermetallics during the further alloying heat treatment. Pore-free green compacts are obtained under almost all the selective forming conditions. However, pores often appear after alloying heat treatment. The forming loading time has a relatively strong influence on the density of the compact. Experiments have also been carried out on various alloying treatments and the effects of the alloying treatment conditions on the mechanical properties of the compacts. It has been demonstrated that Ti-6Al-4V alloy can be fabricated by semisolid forming and the optimum alloying treatment conditions are at 1473 K treating for 7.2 ks, which can result in the best ultimate tensile strength of 1050 MPa and the elongation of 10% in excess of that of the plastic materials.