The microstructure parameters and microhardness of directionally solidified Ti-43A1-3Si alloy

TiAl-based alloy (Ti-43A1-3Si at.%) was directionally solidified at a constant temperature gradient (G = 20 K/mm) in a wide range of growth rates (5-60 mu m/s) by using a Bridgman type directional solidification furnace. The cellular spacing (lambda), lamellar spacing (lambda(L)), volume fraction of Ti(5)Si(3) phases (f(V)) and microhardness (H(V)) were measured. The values of lambda, lambda(L). and f(V) decrease with increasing growth rate (V). The value of H(V) increases with the increasing values of V and lambda(-0.5)(L), and decreases with the increasing values of lambda, and f(V). The dependence of Hv on V, lambda, lambda(-0.5)(L) and f(V) was determined by linear regression analysis. The fitted exponent values obtained in this work were compared with the previous experimental results for similar alloy systems. (c) 2010 Elsevier B.V. All rights reserved.