Zr对Cu-15Cr合金铸态组织及热稳定性的影响  

Effect of Zr on Microstructure and Properties of Cu-15Cr Alloy

作　　者：田伟[1] 刘懿芳 毕莉明[1] 孙玥 

机构地区：[1]上海理工大学,上海200093

出　　处：《稀有金属材料与工程》2018年第2期581-587,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(10874118)

摘　　要：为了研究Zr对Cu-Cr形变原位复合材料组织和性能的影响,采用真空中频感应熔炼技术,制备了Cu-15Cr和Cu-15Cr-0.24Zr合金。利用扫描电子显微镜(SEM)、能谱仪(EDS)、透射电子显微镜(TEM)等表征手段,研究了Zr对Cu-15Cr合金铸态组织及不同温度退火1h后的组织的影响;对两种试验合金进行了冷轧变形,对最终变形量下的试验合金的热稳定性进行了研究。结果表明:Zr的加入,使合金的铸态组织中生成了薄片状的Cu Zr金属间化合物;抑制了共晶Cr相的生成,使共晶Cr含量远低于Cu-15Cr合金,同时,细化了枝晶Cr的尺寸;显著提高了合金的热稳定性,使其在550℃退火1 h后的抗拉强度提高了100 MPa。并通过对试验合金凝固过程的吉布斯自由能(ΔG_(mix))的计算,得出Zr的加入降低了Cu-15Cr合金的液相分离温度,减小了Cu-15Cr合金在凝固过程中动态平衡下的形核驱动力,因此抑制了共晶Cr的生成,这与试验观察到的铸态组织结果一致。Cu-15 Cr and Cu-15 Cr-0.24 Zr alloys were prepared by vacuum medium frequency induction melting technique. The effects of Zr on microstructure of as-cast Cu-15 Cr alloy and microstructure after annealing at different temperatures was studied by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and transmission electron microscopy（TEM）. The tensile deformation test of the two kinds of alloys was carried out, and the thermal stability of the alloy under the final deformation was studied. The results show that the addition of Zr results in the formation of flaky Cu Zr intermetallics in the as-cast microstructure of the alloy, which inhibit the formation of eutectic Cr phase and make the eutectic Cr content much lower than that of Cu-15 Cr alloy. The size of dendritic Cr is refined as well. The addition of Zr significantly improves the thermal stability of the alloy and increases its tensile strength by 100 MPa after annealed at 550 ℃ for 1h. Through the calculation of Gibbs free energy（ΔGmix） in the solidification process of the alloy, it is proved that the addition of Zr reduces the liquid phase separation temperature and decreases the dynamic nucleation driving force of the Cu-15 Cr alloy in the process of solidification, which inhibits the formation of eutectic Cr and is consistent with the experimental results of the as-cast microstructure.

关 键 词：CU-CR-ZR合金 原位复合材料 热稳定性 CuZr金属间化合物 

分 类 号：TG146.11[一般工业技术—材料科学与工程]