Microstructure and Grain Refinement Performance of a New Al-5Nb-RE-B Master Alloy

Abstract

A new kind of grain refiner Al-5Nb-RE-B master alloy with uniform microstructure was prepared by melt reaction method. The effect of Al-5Nb-RE-B inoculation on grain refinement of A356 aluminum alloy was studied. The results show that the Al-5Nb-RE-B master alloy consists of α-Al phase, Al3RE, Nb2Al20RE, and NbB2 phases. When the prepared Al-5Nb-RE-B master alloy was added in an amount of 1.0 wt%, the grain size of the A356 alloy was reduced from 800 μm to 200 μm. Analysis of the A356 alloy solidified at a wide range of cooling rates indicate that 1.0 wt% Al-5Nb-RE-B inoculation exhibits the lowest sensitivity to cooling rate.