Thermodynamic analysis of (Ni, Fe)3Al formation by mechanical alloying

Two-stage amorphization reaction in Ni–Nb–Zr system

“…In this equation R is the gas constant and X A , X B and X C are the mole fraction of A, B and C, respectively [4].…”

“…(3)(4)(5)(6) has taken to be 0, 5 and 8 for solid solutions, amorphous alloys and ordered crystalline alloys, respectively [14]. The chemical enthalpy change of the binary Ni-Zr, Ni-Nb and Zr-Nb systems are calculated by required parameters in Tables 1 and 2.…”

“…Various attempts have been made to develop a valid thermodynamic model for the crystalline-to-amorphous transition during mechanical alloying and to predict the amorphization ability of various alloy systems [4]. The semi-empirical Miedema model is the most successful among them.…”

Study on solid state reactions of nanocrystalline Cu–Ge alloys upon mechanical alloying and annealing

“…The latter is only present in binary solid solutions of transitional-transitional elements in which there are common d bonds and, therefore, is equal to zero in the present calculations. [38][39][40][41] In addition, the heat of formation of alloys containing semiconducting Ge element is less exothermic than the ordinary transition or non-transition metals with common metallic structures. It is because the energy acquisition owing to the optimal filling of the Brillouin zones is generally larger in the pure Ge than in its alloys or compounds.…”

“…Eventually, an entropy change equal to 3?5 J mol 21 K 21 should be considered upon calculation of DS amorphous besides the configurational entropy (equation ( 6)), owing to the disordered structure of an amorphous phase compared to a solid solution. 39,41 From the above analysis, the free energy variations, DG S and DG amorphous , for forming the Cu(Ge) solid solution and the amorphous phase, respectively, from the mixture of pure elements Cu and Ge can be expressed in terms of the constitute elements x Cu and x Ge . The corresponding parameters of equations ( 5) through (15) for the Cu-Ge binary system are presented in Table 1 and DG S and DG amorphous calculated are illustrated in Fig.…”