扭转变形与退火处理对再生铜杆显微组织和性能的影响
Influence of Torsional Deformation and Annealing on Microstructure and Properties of Recycled Copper Rod
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摘要: 对采用火法精炼高导电(FRHC)废杂铜精炼工艺+连铸连轧工艺制备的直径8 mm再生铜杆进行720℃扭转变形和500℃×60 min退火处理,研究了扭转变形和退火处理对其显微组织、力学性能和导电性能的影响。结果表明:在连铸连轧过程中再生铜杆组织中产生孪晶,扭转变形导致的孪晶交叉、孪晶与位错等的交互作用使得晶粒发生细化;扭转变形后再生铜杆的抗拉强度由未扭转变形的215 MPa提高到273 MPa,但断后伸长率由40%降低到21%,硬度增大,导电率由99.37% IACS降低至86.78% IACS;再进行退火处理后,再生铜杆组织形成尺寸更均匀的等轴晶,抗拉强度降至208 MPa,断后伸长率提高到55%,硬度降低,导电率增至98.21% IACS。Abstract: Torsional deformation at 720 ℃ and 500 ℃×60 min annealing treatment were carried out on the 8 mm diameter recycled copper rods prepared by fire refined high conductivity (FRHC) waste copper refining process and continuous casting and rolling process. The effects of torsional deformation and annealing treatment on the microstructure, mechanical properties and electrical conductivity of the copper rod were studied. The results show that twins were generated in the recycled copper rod structure during continuous casting and rolling process, and the twin crossover and the interaction between twins and dislocations caused by torsional deformation made the grains refined. The tensile strength of the recycled copper rod after torsional deformation increased from 215 MPa without torsional deformation to 273 MPa, but the elongation after fracture decreased from 40% to 21%;the hardness increased and the electrical conductivity decreased from 99.37%IACS to 86.78%IACS. After annealing treatment, the recycled copper rod had a structure with equiaxed crystals with more uniform size. The tensile strength was reduced to 208 MPa, while the elongation after fracture increased to 55%; the hardness decreased and the electrical conductivity increased to 98.21% IACS.
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