The effect of Al–5Ti–1B grain refiner on the structure and tensile properties of Al–20%Mg alloy

Abstract

In current research, the effect of Al–5Ti–1B grain refiner on the structure and tensile properties of Al–20%Mg alloy have been investigated. Scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis were utilized to study the microstructure and fracture surfaces of samples. Microstructural analysis of the cast alloy showed the dendrites of a primary α-phase solid solution within the eutectic matrix which consists of β-Al3Mg2 intermetallic and α-solid solution. The results indicated that adding Al–5Ti–1B to the alloy caused a significant rise in the ultimate tensile strength (UTS) and elongation values from 168MPa and 1.2% to maximum 253MPa and 2.4%, respectively. The main mechanisms for the observed enhancement were found to be due to the refinement of grains during solidification and also segregation of Ti to the tip of Al (α) dendrites. This phenomenon controls the dendritic growth and changes the morphology of this phase from interconnected coarse dendrites to a star-like morphology.