Study of the precipitation, nucleation, and grain growth of phases in the ZL201 cast aluminum alloy by integrated calculations

Abstract

Abstract The purpose of this study is to investigate the influence of alloy composition on the evolvement rule of microstructure for ZL201 cast aluminium alloy. The ZL201 casting samples with different components were prepared by gravity diecasting process, the phase composition was characterized and calculated by x-ray diffraction (XRD) and thermo-calc (TC) software respectively, the evolvement rule of microstructures was observed by metallographic microscope (OM) and scanning electron microscope (SEM), and simulated by ProCAST software. The results show that the Al2Cu (θ) formed by Cu and Al matrix, which increased the free energy and reduced the precipitation temperature for the alloy system. For the microstructure of ZL201, the nucleation direction of Al-Cu was along the positive direction of z-axis, the morphology was a regular ribbed morphology; Al-Mn and Al-Ti were along the negative directions of x- and y-axis and morphologies were columnar. Besides, the nucleation mode of casting center was dominated by the growth pattern of Al-Cu, and that of casting surface was dominated by Al-Ti and Al-Mn.