Microstructures and Mechanical properties of Spray deposited and Heat-treated Al-25Mg2 Si-2Cu alloy

Abstract

The microstructural characteristics and  mechanical properties of Al–25Mg₂Si-2Cu alloy were investigated. The alloy produced by spray atomization and deposition techniques followed by hot compression(HC) and age hardening(AGH) at 180ºC for 2h and 2h  intervals after the solution heat treatment. The microstructure features of as cast, spray deposited (SD),hot compressed and heat-treated alloys were studied. the results show the microstructure of spray-deposited alloy mainly comprised of a uniform distribution of   intermettalics   ?-Mg₂Si phase, ?- Al₂Cu and Q phase in Al-matrix. Eliminating the porosity of deposit and fragmentation of the ? And Q phases is the main features during hot compression. After solution treating and age hardening, the microstructure found to be comprised of mainly Mg₂Si phase in a fine spherical form. Large quantity of ?- Al₂Cu phase and Q Phase less than 50 nm in size uniformly distributed in the Al- matrix during aging. These fine ? particles combined with the ? can significantly increase the tensile strength and hardness of the alloy. In the peak-aged condition is because of high concentration of Mg₂Si and Al₂Cu metastable phases. The microstructural features of alloys been investigated through Optical (OM) and Scanning electron microscopy (SEM) and analyses of phases were carried out using Energy dispersive X-ray( EDS).The improvement in the tensile and hardness properties of studied alloys was investigated by tensile test and  micro- hardness.

Keywords: Al-Mg₂Si alloy, Spray deposition, Age hardening, Microstructure, Mechanical properties, Micro hardness