变形和热处理对Cu-0.26Cr-0.24Sn合金组织及性能的影响

    Effects of Deformation and Heat Treatment on Microstructure and Properties of Cu-0.26Cr-0.24Sn Alloy

    • 摘要: 采用气保护炉熔炼了Cu-0.26Cr-0.24Sn合金,而后对棒状铸锭依次进行了旋锻变形、固溶和时效处理,用光学显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)以及透射电子显微镜(TEM)等手段,分析了不同旋锻变形量、固溶和时效条件下合金的微观组织及力学、电学性能。结果表明:旋锻变形后的晶粒组织随着变形量的增加而细化,提高了合金的强度,而导电率稍有下降;960℃保温1 h后微米级富Cr析出物充分固溶。固溶时效后发生再结晶并产生再结晶织构,平行于轴向的<111>晶向增加,再结晶织构的强度随旋锻变形量的增加而增加,可提高屈服强度,但降低伸长率。时效后纳米级的富Cr颗粒析出,硬度和导电率显著上升。合金经过75%的旋锻变形,在450℃时效2.5 h后,该合金的抗拉强度和导电率分别达到476.5 MPa、68.7% IACS,可获得较好的强度和导电率配合。

       

      Abstract: Cu-0.26Cr-0.24Sn alloy was smelted using the gas protection furnace, and then the cast ingots were carried to rotary swaging, solid solution and aging treatment. The effects of deformation and heat treatment on the microstructure and properties of the alloy were characterized by optical microscope(OM), scanning electron microscope(SEM), X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results show that the microstructure alloy grains can be refined with increase of the swaging deformation strain, which improve the strength of the alloy, while the conductivity decreases slightly.After solid-solution treatment at 960 ℃for 1 h, the micron-sized Cr-rich precipitates are fully dissolved.During solid-solution and aging process, the alloy recrystallizes and forms recrystallization texture, makes the < 111> orientations parallel to the axis increases. The intensity of the recrystallized texture increases with increasing swage deformation strain, which improves the yield strength but decreases the elongation. After aging, the nano-sized Cr-rich particles are precipitated from the Cu-matrix, and the microhardness and conductivity increase significantly.The tensile strength and conductivity of the alloy by 75%rotary swaging and aging at 450 ℃for 2.5 h can reach 476.5 MPa, 68.7%IACS, respectively, and a superior combination of strength and electrical conductivity is obtained.

       

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