A criterion for evaluating glass-forming ability of alloys

A criterion defined as theta = (T-x+T-g)/T-l[(T-x-T-g)/T-l](alpha) (where T-x is the onset crystallization temperature. T-g is the glass transition temperature, T-l is liquidus temperature. and alpha is an exponent) is proposed to evaluate the glass-forming ability of alloy systems. Regression analysis between the logarithm of the critical cooling rate In R-c and theta yields value of alpha = 0.0728. There exists a fine linear relationship between criterion theta and In R-c with a coefficient of determination R-2 = 0.942. The obtained relationship can be expressed as: In R-c = (30.10 +/- 0.91)-(27.93 +/- 0.97) theta. The comparisons of theta with all other relevant parameters: phi{=T-rg[(T-x-T-g)/T-g](0.143)}, gamma[=T-x/(T-l+T-g)], Trg(=T-g/T-l), beta[=TxTg/(T-l-T-x)(2)], delta[=T-c/(T-l-T-g)] show that this criterion has the best ability for evaluating the GFA of alloys. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3255952]