(燕山大学 材料工程学院， 秦皇岛 066004)
摘 要: 研究了添加Mn、 Ni对ZA27合金组织和性能的影响。 结果表明： 适量Mn、 Ni的添加在不明显降低室温强度的条件下， 显著提高了合金的高温性能； 同时添加质量分数为0.5%Mn和0.5%Ni使铸态ZA27合金非平衡网状三相共晶中出现大量富镍相粒子， 在250 ℃、 拉伸机横梁移动速率为100 mm/min条件下的瞬时抗拉强度27.2 MPa比未加Mn、 Ni的合金提高46%； Mn、 Ni的添加使280 ℃、 初始应变速率6.67×10-2 s-1条件下的超塑性拉伸的稳态流变应力由12.4 MPa提高到24.6 MPa， 比未加Mn、 Ni的合金提高98%。 扫描电镜观察与X射线能谱分析表明， Mn、 Ni显著提高超塑性拉伸的稳态流变应力的主要原因与“离位析出”富含Cu、 Ni、 Mn的粒子有关。
关键字: ZA27合金； Mn-Ni合金化； 超塑性； 力学性能
microstructures and mechanical properties
of ZA27 alloy
（College of Materials Science and Technology,
Yanshan University, Qinhuangdao 066004, China）
Abstract: The effect of Mn and Ni additive on the microstructure and mechanical property of ZA27 alloy was studied. The appropriate additive of Mn and Ni can remarkably raise the strength in high-temperature, under condition that room temperature strength only decreases slightly. When the additives of Mn and Ni are all 0.5% in the mean time, great quantities of Ni-enriched particles appear in reticulate unbalanced three-phase eutectic of the as-cast ZA27 alloy, which made the instantaneous tensile strength of the alloy lift to 27.2 MPa that is 46% higher than that of not undergone Mn-Ni alloying under the condition of 250 ℃ and 100 mm/min. In the super plastic tensile testing with 280 ℃, the initial strain speed of 6.67×10-2 s-1, Mn-Ni additive made the stable flowing stress rise from 12.4 MPa to 24.6 MPa that is 98% higher than that of without Mn-Ni additives. Concluded from the results of TEM and DES analyses, the cardinal reason of the remarkable enhancement of stable flowing stress in super plastic tensile testing is directly related to the precipitation of particles enriched Cu, Ni and Mn.
Key words: ZA27 alloy; Mn-Ni alloying; super plasticity; mechanical property
