Effect of growth rate on microstructure parameters and microhardness in directionally solidified Ti-49Al alloy

Intermetallics Ti-49Al (at.%) alloy was directionally solidified with different growth rates (V = 5 mu m/s-30 mu m/s) at a constant temperature gradient (G = 12.1 K/mm) by using a Bridgman type directional solidification furnace. The primary dendritic spacing (lambda), interlamellar spacing (lambda(L)), and microhardness (HV) were measured. Effect of V on HV, lambda and lambda(L) was experimental investigated. The dependencies of lambda, lambda(L) and HV on the growth rate were determined by using linear regressing analysis. According to the result, the values of lambda and lambda(L) decrease with the increasing of V. and the values of HV increase with the increasing of V and with the decreasing of,. and L. The results were compared with previous similar experimental results for TiAl-based alloys. (C) 2011 Elsevier Ltd. All rights reserved.