THERMAL-EXPANSION AND BOND STRENGTH IN A A(2)(II)B(IV) MELTS (MG2SI, MG2SN, MG2PB)

The specific volume of the Mg2Si, Mg2Sn, and Mg2Pb melts is measured a s a function of temperature. The obtained data, fitted to equations of the form V-sp(-1) = A + B(T-T-m), are used to calculate the thermal e xpansion coefficients of the melts. The Debye characteristic temperatu res and root-mean-square dynamic atomic displacements at the melting p oint are estimated. Melting is accompanied by a shall, increase in the thermal expansion coefficient, especially in the case of Mg2Si, and a decrease in Debye characteristic temperature. These findings testify to significant changes in the vibrational spectra of the A(2)(II)B(IV) compounds on melting.