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借助显微硬度计、光学显微镜、扫描电镜、X射线衍射分析、腐蚀实验和拉伸测试等手段,研究了锆、锶复合微合金化铸态镍铝青铜的硬度、组织、耐蚀性能和力学性能。结果表明:与未微合金化铸态镍铝青铜(Cu-8.87Al-5.22Fe-4.48Ni-1.08Mn-0.53Zn)相比,锆、锶复合微合金化铸态镍铝青铜(Cu-9.86Al-5.84Fe-4.46Ni-1.03Mn-0.6Zn-0.048Zr-0.03Sr)的相组成没有显著变化,都由α相、β相、γ2相和κ相组成。但是微合金化镍铝青铜的α相和κIV相显著细化,共析组织(α相+κIII相)也大幅细化,合金硬度从212.1 HV提高到216 HV。由于腐蚀优先发生在共析区域内,而共析组织的细化降低了其产生连续腐蚀通道的概率,促进了合金的均匀腐蚀性能和电化学腐蚀性能的全面提高(在3.5%Na Cl水溶液中均匀腐蚀速率和电化学腐蚀速率分别降低2.9%和49.6%);晶粒细化和颗粒弥散强化提高了微合金化镍铝青铜的力学性能,其抗拉强度和屈服强度分别提高到676.6 MPa和260.3 MPa(分别提高4.06%和4.07%)。
The hardness, microstructure, corrosion resistance and mechanical properties of zirconium and strontium composite microalloyed as-cast nickel-aluminum bronze were investigated by means of microhardness tester, optical microscope, scanning electron microscopy, X-ray diffraction analysis, corrosion test and tensile test performance. The results show that compared with non-microalloyed nickel-aluminum bronze (Cu-8.87Al-5.22Fe-4.48Ni-1.08Mn-0.53Zn), zirconium and strontium composite microalloyed as-cast nickel aluminum bronze Al-5.84Fe-4.46Ni-1.03Mn-0.6Zn-0.048Zr-0.03Sr) did not change significantly and consisted of α phase, β phase, γ2 phase and κ phase. However, α phase and κIV phase of the microalloyed nickel-aluminum bronze were significantly refined. The eutectoid structure (α phase + κIII phase) was also greatly refined. The hardness of the alloy increased from 212.1 HV to 216 HV. Since corrosion preferentially occurs in the eutectoid region, the refinement of the eutectoid structure reduces its probability of producing continuous corrosion channels and promotes an overall increase in the uniform and electrochemical corrosion behavior of the alloy (in 3.5% NaCl aqueous solution Uniform corrosion rate and electrochemical corrosion rate decreased by 2.9% and 49.6%, respectively). The grain refinement and dispersion strengthening enhanced the mechanical properties of the microalloyed nickel-aluminum bronze. The tensile strength and yield strength increased to 676.6 MPa and 260.3 MPa (4.06% and 4.07% respectively).