Large Deformation The Asynchronous Arb Preparation Of Ultrafine Grained Copper Process And Its Microstructure Evolution Study

Grain refinement is a kind of effective method to improve intensity of materials. Studies have shown that materials will demonstrate a series of unusual physical, chemical and mechanical performance when crystalline grain size is reduced to 1μm. Methods to prepare ultra-fine-grained materials are numerous, of which severe plastic deformation gets more and more focus because of its merits of preparing dense bulk material with simple craft and little cost. ARB is one of technologies with prospect of industrialization that can reduce grain size from normal grade to submicron even nanometer. Superior to the routine pile rolling ,severe plastic deformation with Asymmetrical -ARB as its machining process has strong ability to refine grain, improving the precision rolling method of the products greatly .In the paper, the present state of ultra-fine-grained materials, severe plastic deformation and Asymmetrical-ARB are introduced in detail; the craft to fabricate ultra-fine-grained copper using Asymmetrical -ARB is studied fully; the problem of combination of interface is settled; the affect of homogenizing annealing, annealing and rolling method on mechanical properties of materials prepared by Asymmetrical-ARB is discussed and analyzed when control parameters of rolling mill such as the press—ratio, the asynchronous rate, rolling—speed are fixed, and a kind of craft that meets to requirement of experiment is made out. Studies have shown: Asymmetrical than 1.08, rolling speed as 100r/min, each is it press quantity 50% rolling mill under the control parameter to keep, Asymmetrical -ARB prepares ultra detailed brilliant copper craft: 600 degrees Centigrade keeps warm melting homogenizing annealing in 60 minutes under the craft , the stress relief annealing to roll two pass each time, go 130 degrees Centigrade of stress annealing temperature , keep warm for 30 minutes.By testing different recrysrallization regulation at different passes, the law that the organization developed under different recrystallization regulation is analyzed . And the stress relief annealing regulation is confirmed that can not only dispel work —harden, but also produce even fine grain under different deformation amount. Having fabricated the ultra-fine-grained copper, the change of the mechanics performance of material is discussed initially.Studies have also shown: Asymmetrical -ARB is a kind of efficiency method to prepare ultra-fined grain.It can make ultra-fine grain of 200-500nm through different recrystallizationregulation when true strain is 3.1 — 3.9. Compared with the unrolled copper that keep warm for 60 minutes, supreme tensile strength of ultra-fine- grained copper is raised by 1.24 times; supreme yield strength by 6.65 times.And the finally thinning degree of grain depends on rolling size of the previous grain, rolling deformation amount and process that the crystallization annealing.