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研究了2种变形处理方式下的超细晶Cu-Cr-Zr合金从室温到600℃的拉伸性能、断口微观组织特征及其断裂机制.结果表明:经4道次等径弯曲通道挤压(ECAP)+时效+4道次ECAP变形处理的合金(No.1试样)的抗拉强度随拉伸温度的升高而降低,室温时,合金抗拉强度为577.17 MPa,延伸率为14.6%;在300℃开始发生动态再结晶软化,抗拉强度迅速减小,到600℃时抗拉强度仅为59.12 MPa.经过8道次ECAP+时效变形处理的合金(No.2试样),室温抗拉强度为636.71 MPa,延伸率为12.1%;从400℃开始析出相对晶界的钉扎作用开始逐渐减弱,抗拉强度大幅降低,600℃时的抗拉强度为65.20 MPa.No.2试样比No.1试样具有更好的室温性能和热稳定性.2种方式处理下合金延伸率随拉伸温度的升高而升高,在高温下都表现出超塑性.高温拉伸断口微观形貌为大量密集、深入的韧窝,其高温断裂机制为微孔聚集的韧性断裂.
The tensile properties, fracture microstructure and fracture mechanism of ultrafine-grained Cu-Cr-Zr alloy from room temperature to 600 ℃ were studied in two kinds of deformation treatments.The results show that after 4 times of equal-diameter curved passages (ECAP) + aging +4 pass ECAP deformation of the alloy (No.1 sample) tensile strength decreases with the increase of stretching temperature, the room temperature, the alloy tensile strength of 577.17 MPa, elongation of 14.6 %; At 300 ℃, dynamic recrystallization softening began to occur, the tensile strength decreased rapidly, and the tensile strength was only 59.12 MPa at 600 ℃ .After 8 passes of ECAP + aging treatment (No.2 sample), room temperature The tensile strength was 636.71 MPa and the elongation was 12.1%. The pinning effect of the relative grain boundary started to precipitate at 400 ℃ gradually decreased, the tensile strength was greatly reduced, and the tensile strength at 600 ℃ was 65.20 MPa. Like sample has better room temperature performance and thermal stability than the No.1 sample.The elongation of the alloy increases with the increase of the drawing temperature and the superplasticity at high temperature in the two ways.The high temperature tensile fracture Micro-morphology is a large number of intensive, in-depth dimples, the high-temperature fracture mechanism for the accumulation of micro-ductile fracture.