Thermodynamic investigations of Al-Mg, Al-Li-Mg, Mg-Y, Mg-Si, Cu-Mg-Ni and Al-Mg-Si alloys Final report

The enthalpy of mixing #DELTA#H of liquid binary and ternary aluminium and magnesium alloys has been determined to understand the thermodynamics and the phase equilibria of these light alloys. The experiments were performed using high-temperature isoperibolic type of solution calorimeter. The obtained #DELTA#H-values of liquid Al-Mg alloys follow a regular solution behaviour with a minimum value of -2.2 kJ mol"-"1. The extrapolated #DELTA#H-values of Mg-Y and Mg-Si alloys show a maximum at about 23 at.% Y and 42 at.% Si respectively. The enthalpy of formation, the enthalpy of melting and the heat capacity of Mg_2Si, Mg_2Ni, MgNi_2, CuMg_2 and Cu_2Mg have been determined calometrically. The enthalpy of mixing of liquid Al-Li-Mg alloys was measured between 870 and 1030 K starting from all three bordering systems as bath material and adding the respective third component. The minimum value of #DELTA#H (i.e. -10 kJ mol"-"1) is to be observed in the binary Al-Li system at the stoichiometric composition AlLi. (orig.)SIGLEAvailable from TIB Hannover: F95B855+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany); Commission of the European Communities (CEC), Brussels (Belgium)DEGerman