Paper Title
Microstructure, Microhardness and Tensile Properties of Al-Mn-0.5si Alloy Produced by Directional Solidification

The directional solidification process of ternary Al-1.94Mn-0.5 Si eutectic alloy within a wide growth velocity range from 8.3 to 978 μm/s was accomplished at a constant temperature gradient of 4.9 K/mm. The microstructures of produced samples were characterized by using optical microscopy (OM), scanning electron microscopy (SEM) and Energy dispersive x-ray analysis (EDX). Dendritic microstructures were observed in the directionally solidified samples. The dendritic spacing tends to decrease with increasing growth velocity. As growth velocity increases, the dendritic spacing decreased from 160 to 68 􀀀m. Microhardness and tensile strength at room temperature were examined by tensile tests. It was found that the microhardness and ultimate tensile strength increased with increasing growth velocity, which ranged from 8.3 to 978 μm/s. Exponent values of the V for the microhardness and tensile strength were calculated as 0.05 and 0.09, respectively. Fracture surface images of the studied alloys were analyzed depending on growth velocity. The fracture mode transforms from ductile form to less ductile form with the increase of the growth velocity. Index Terms— Fracture, microhardness, microstructure, tensile strength, Ternary eutectic alloy,