Reactive diffusion in a mixture of copper and aluminum powders
- 23 Downloads
Reactive diffusion in a mixture of copper and aluminum powders and in a Cu-Al bimetal results in the formation of an intermediate layer composed of new phases arranged between the aluminum and the copper in the following order;θ (CuAl2), η2 (CuAl), and γ2 (Cu2Al).
The kinetics of growth of the individual phases and the layer as a whole in a mixture of copper and aluminum powders and a Cu-Albimetal obeys the parabolic law X2=K(t-t0). The latent period of a powder mixture is a very short, and the energy of activation for phase growth in it is approximately 1.5 times that in a bimetal. During the annealing of a powder mixture for long period of time, deviations from a parabolic law are observed, which are due to dissolution processes at the phase interfaces and the presence of only a limited amount of aluminum participating in diffusion.
The high reactivity of a powder mixture ensures that the rate ofθ phase growth at all temperatures is higher in such a mixture than in a bimetal. The rates of growth of the whole layer and the η2+γ2 phase layer in a powder mixture and a bimetal are approximately equal. The initial porosity of specimens and the presence of oxides on the surfaces of powder particles, which determine the area and degree of contact between dissimilar particles, exert a strong influence upon the rate of phase growth during reactive diffusion.
KeywordsCopper Phase Growth Latent Period Powder Particle Powder Mixture
Unable to display preview. Download preview PDF.
- 1.J. J. Huet, Metallurgie (Belg.),3, No. 3, 49 (1962).Google Scholar
- 2.M. K. Asundi and D. R. F. West, J. Inst. Metals,92, No. 12, 428 (1964).Google Scholar
- 3.D. I. Lainer and A. K. Kurakin, Tsvetn. Metally, No. 10, 64 (1964).Google Scholar
- 4.N. M. Voropai and A. Ya. Shinyaev, Metal, i Term. Obrabotka Metal., No. 12, 55 (1967).Google Scholar
- 5.F. L. Lokshin, F. G. Gol'der, and R. M. Sizova, Metal. i Term. Obrabotka Metal., No. 11, 72 (1967).Google Scholar
- 6.A. Ya. Shinyaev and N. M. Voropai, Diffusion in Metals and Alloys [in Russian], Tula (1968).Google Scholar
- 7.L. N. Larikov, A. V. Lozovskaya, et al., in: Metal Physics [in Russian], Vol. 28, Naukova Dumka, Kiev (1969), p. 5.Google Scholar
- 8.N. I. Kononchuk, Methods of Evaluating the Fatigue Strength of Heat Resisting Alloys [in Russian], Metallurgiya, Moscow (1966).Google Scholar
- 9.I. B. Borovskii and V. I. Rydnik, Izv. Akad. Nauk SSSR, Ser. Fiz.,31, No. 6, 1009 (1967).Google Scholar
- 10.V. I. Rydnik and I. B. Borovskii, Zavod. Lab.,33, No. 8, 955 (1967).Google Scholar
- 11.K. V. Savitskii, V. I. Itin, and Yu. I. Kozlov, Poroshkovaya Met., No. 1, 5 (1966).Google Scholar
- 12.P. P. Budnikov and A. M. Ginstling, Reactions in Mixtures of Solid Substances [in Russian], Stroiizdat, Moscow (1971).Google Scholar