【摘要】 研究了镁锆合金的晶粒细化机理 ,制备了不同锆含量的镁锆合金 ,在制备过程中采用了含有SF6的混合气进行气体保护 .研究了镁锆合金凝固组织与性能 ,以及应变、频率、温度和锆含量对合金阻尼性能的影响 ,利用减振实验验证了合金的阻尼性能 .结果表明 :随着合金锆含量的增加 ,晶粒尺寸细化为 30 μm ,同时合金力学性能得到了改善 .研究还表明 ,合金阻尼性能和频率无关 ,但随着应变量的增加而不断提高 ,并且在ε =1× 1 0 -4时 ,损耗因子达到 5 .3× 1 0 -2 高阻尼水平 .采用Mg Zr合金制作的仪表基座对振动信号的传递比为 1 .88,显著低于ZM6和LY1 2合金基座的传递比更多还原

【Abstract】 Grain refining mechanisms of magnesium-zirconium alloys were investigated. Mg-Zr alloys were prepared and a mixture gas containing SF 6 was used for protection during melting and casting. The microstructure and properties of Mg-Zr alloys and the effects of strain, frequency, temperature as well as the addition of Zr on the damping capacity were studied. The damping capacity was validated with vibration attenuation experiment. The results show that zirconium is a potent grain refiner for magnesium alloys. The average grain size can be reduced to 30?μm for Mg-0.45%Zr(mass fraction) alloy and the mechanical properties of Mg-Zr alloys can be dramatically improved with increasing zirconium content. It is also found that the damping capacity has almost no connection with frequency, but increases with strain, the loss factor reaches 5.3×10 -2 at a strain amplitude of 1×10 -4. The value of transfer ratio of Mg-Zr base is 1.88 and obviously less than that of ZM6 alloy base and LY12 alloy base.更多还原