Effect Of Cold Rolling And Recrystallization Annealing On Microstructure And Properties Of Ta-2.5W Alloy

Tantalum-tungsten alloy ingots fabricated by electron beam melting method have coarse grains.Base on this,this paper focuses on fabricating tantalum-tungsten alloys which adding TiC by powder metallurgy method to obtain fine grains.The effect of TiC content on the microstructure and properties of Ta-2.5W alloy were studied.The effects of cold rolling with different reduction and annealing at different temperature on the microstructure and properties of Ta-2.5W alloy obtained by electron beam melting were also studied.The properties of the material were tested by universal testing machine.The microstructure of the alloys were analyzed by means of optical microscope(OM),scanning electronmicroscope(SEM),backscatter electron diffraction analysis(EBSD),and transmission electron microscopy analysis(TEM),respectively.The conclusions are shown as follows:(1)The mechanical properties of Ta-2.5W with 0.3wt% TiC addition is the best.Fractured mode of the alloys with TiC addition is mainly transgranules,and TiC grains can be found in the grain boundary,besides the fine grains were obtained.(2)The main texture components of the alloys are still ?-fibre texture and ?-fibre texture at different reduction.With the increase of reduction,the texture changes to{100}<110>.The recrystallization degree of cold rolled sheets changes after annealing at different temperatures and times.For 20% reduction,the microstructure is still partly recovered,and the new equiaxed grains are still formed after annealing for 2 h at1450?.With the further increase of reduction,the recrystallization degree of the alloy increases.when the reduction reaches to 80%,the recrystallization completes.(3)In the same annealing conditions(1450?-1h),the recrystallization degree of the material increases with the increase of reduction.For 20% reduction,?-fiber texture and strong {001}<130> texture are formed;with further increase of reduction,{001}<uvw>texture is weakened,and the type of ?-fiber texture maintains;when the reduction reaches to 80%,the texture of annealed ?-fiber increases relatively,and the orientation turn to {001}<150>.The equiaxed grains account for 95.67% of 80% reducted Ta-2.5W alloy can be obtained by annealing at 1450? for 1h.The plasticity of Ta-2.5W alloy with 80% reduction improves obviously by annealing treatment.