Research On The Intermediate Annealing Of In-situ Deformed Cu-12.8%Fe Composites

With the rapid development of human society, the much higher request is bring up for the comprehensive property of high-strength and high-conductivity Cu alloy. In-situ Deformed Cu-based Composites,with high strength and high conductivity,becomes the hot topic of this field. In In-situ Deformed Cu-based composites, In-situ Deformed Cu-Fe Composites which has lower cost,good melting property,fine plasticity,excellent strengthening effect,attracts vast attention.However,low conductivity is the chief drawback of In-situ Deformed Cu-Fe Composites,which is caused by the high solubility of Fe in Cu matrix. Intermediate annealing is the critical process which can improve conductivity by promoting the precipitation of Fe. In this thesis, In-situ Deformed Cu-12.8%Fe Composites is manufactured by vacuum induction melting,turning,hot swaging and drawing-annealing-drawing process.Then.the variation of structures and properties with annealing-drawing is researched. The main conclusions are as follows:(1) There’s no obvious microstructure evolution after300℃annealing. There’s also no obvious microstructure evolution after450℃annealing within short holding and cooling time, but with the extension of holding and cooling time,some of the Fe fibers become broken and spheroidal, which is caused by recrystallization. When the annealing temperature is increased to600℃, broken and spheroidal phenomenon become more obvious. The higher temperature of annealing,the more obvious broken and spheroidal phenomenon. The longer holding and cooling time,the more obvious broken and spheroidal phenomenon. The speed and proportion of recrystallization is closely related to annealing temperature, holding and cooling time.(2) The strength reduces after annealing. The higher temperature of annealing.the greater strength reduction. The longer holding and cooling time, the greater strength reduction. The strength increases with the increase of drawing ratio. The strength of annealing increases more rapidly with the increase of drawing ratio than No HT,and it exceeds the value of No HT after more deformation. The conductivity greatly increase after annealing. The conductivity increase greater after450℃annealing. The longer holding and cooling time, the greater conductivity increase. The conductivity decreases with the increase of drawing ratio.(3) The comprehensive property decreases greatly after annealing. The higher temperature of annealing,the greater comprehensive property reduction. The longer holding and cooling time, the greater comprehensive property reduction. The comprehensive property increases with the increase of drawing ratio. The increasing speed of comprehensive property varies with different annealing process.The better annealing temperature is450℃.When the material is annealed under,the conductivity value exceeding No HT increases with the increase of drawing ratio.(4) Within the annealing processes of this thesis,the better intermediate annealing processes are450℃/1h/48h and450℃/12h/48h.Until drawing ratio η=9.93, the comprehensive property of450℃/1h/48h and450℃/12h/48h exceed No HT by26%.The material has higher strength after450℃/1h/48h process,and has higher conductivity after450℃/12h/48h process.(5) The better comprehensive property values are as follows:570MPa/63.53%1ACS (450℃/1h/48h,η=8.19),985MPa/58.87%IACS (450℃/1h/48h,η=9.93),520MPa/67.05%IACS (450℃/12h/48h,η=8.19),935MPa/62.61%IACS (450℃/12h/48h,η=9.93)...