Effect of Strontium Modification and Heat Treatment on Microstructure of Al-319 Alloy

319 type aluminium alloy is a high strength heat treatable alloy having wide range of engineering applications. The most common chemical treatment consists of modifying the morphology of silicon eutectic phase from acicular to fibrous form, thus improving the mechanical properties. The basic properties of this alloy can be improved by the proper choice of melt treatments such as grain refinement and modification followed by precipitation hardening treatment at optimum heat treatment condition of temperature and time. The present study envisages optimizing the ageing condition of 319 alloy. The melt treatment involves grain refinement with Ti-B master alloy and modification with Al-Sr master alloy. The alloy cast in permanent mould is machined to make samples for evaluation of mechanical properties and metallographic studies. The machined samples were subjected to solution treatment at a constant temperature of 500°C and aged at different temperatures. The effect of ageing on microstructure will be discussed.