Unusual kinetics of strain-induced diffusional phase transformations in Cu-Cr-Zr alloy

This paper reports experimental results demonstrating nonmonotonic changes of the solid solution concentration in the process of high-pressure torsion of the preliminary aged Cu-Cr-Zr alloy. The solid solution concentration which is very low in the initial state passes through a maximum before it finally stabilizes at a lower value. Such a behavior is, strictly speaking, impossible for a purely diffusion-controlled process under stationary conditions. Observations on the evolution of the second phases particles in the course of deformation suggest a possible mechanism behind this phenomenon. Severe deformation causes refinement of the particles initially present in the alloy by, most probably, quasi-brittle fracture, what creates fragments with sharp edges and makes possible their partial dissolution by Gibbs-Thomson mechanism. The morphology and sizes of the partially dissolved fragments as well as of newly precipitated particles make them less susceptible to fracture than those formed by the preliminary aging. So, under severe deformation, unlike the usually considered models, a “dissolving” subset of particles evolves not only due to diffusion; in the other words, the deformation creates a difference between “dissolving” and “precipitating” subsets of particles. As combined fracture and dissolution transform the initial ensemble of particles, the dissolution gradually slows down unlike the precipitation, which rate is controlled by the solution concentration and density of precipitation sites. As a result, these processes first reach a transitional balance, corresponding to the maximum concentration, and later a stable dynamic equilibrium on its lower level.

The effect of preliminary treatment with subsequent aging on structural-phase state and mechanical properties of β titanium alloy

E.V. Naydenkin, I.V. Ratochka, I.P. Mishin, O.N. Lykova, O.V. Zabudchenko

Experience in obtaining laminated aluminum composites by asymmetric accumulative roll bonding

O.D. Biryukova, A.M. Pesin, D.O. Pustovoitov

Influence of carburization on the structure and properties of functional diffusion coatings based on titanium carbide on TiC-WC-Co and WC-Co alloys

A.G. Sokolov, E.E. Bobylyov, R.L. Plomod'ialo

Features of the carbide phase degradation under heating and deformation

T.S. Skoblo, O.Y. Klochko, V.N. Romanchenko, E.L. Belkin

Structure and strength of Al-Mn-Cu-Zr-Cr-Fe ALTEC alloy after radial-shear rolling

A.N. Petrova, D.Y. Rasposienko, V.V. Astafyev, A.O. Yakovleva

The influence of microalloying and heat treatment on the structure and properties of Galfenol with high gallium concentration

V.V. Palacheva, V.V. Cheverikin, E.N. Zanaeva, F. Emeis, V.V. Korovushkin, H. Wang, C. Jiang, I.S. Golovin

The formation of friction-induced nanocrystalline structure in submicrocrystalline Cu-Cr-Zr alloy рrocessed by DCAP

I.V. Khomskaya, A.E. Kheifets, V.I. Zel'dovich, L.G. Korshunov, N.Y. Frolova, D.N. Abdullina