STUDY INTO LASER-HEATING OF TI-14AL-21NB ALLOY TO IMPROVE PROPERTIES

Ti-14Al-21Nb alloy may find a potential application in advanced struct ures. On the other hand, incompatible atomic configurations at the gra in boundaries render the grain boundary regions weak, which, in turn, provides possible crack development and propagation along these bounda ries, i.e. due to room temperature slip behaviour of intermetallic all oys, nucleation and propagation of cracks become the mode of deformati on. Considerable research has been carried out to solve the poor ducti lity of intermetallic alloy knowing the fact that altering the crystal structure and reducing slip distance by creating a small grain size s tructure may be one way of solving the problem. Consequently, laser he ating at pulses 1 mu s can provide a cooling rare of the order of 10(6 ) K/s, which, in turn, makes it possible to change the metallurgical s tructure of the alloy to a desired structure. In the present study, a theoretical model based on Fourier analysis is carried our to predict the cooling rate after the laser pulse irradiation. An experiment is c arried out to measure rite cooling rate. The study is extended to incl ude experimental investigation into metallurgical changes due to laser pulse.