Of Mg-12gd-3y-0.5zr Alloy, Mechanical And Damping Properties Of Study

Magnesium alloys are attractive by high specific strength, high specific stiffness and good damping vibration attenuation. However, the applications of magnesium alloys are limited due to their poor plasticity and low strength, as a result of which the damping capacity of noise absorption capacity has been ignored. Mg-12Gd-3Y-0.5Zr(wt.%) magnesium alloy, which exhibits excellent mechanical properties, has been investigated in this paper. Mechanical property dependent on positions and heat treatments are experimented to confirm the optimum way of Mg-12Gd-3Y-0.5Zr treatments under extruded condition, where OM, SEM and XRD are used for investigating the evolutions of microstructure during heat treatments. Damping capacity tests are conducted on samples of extruded state, extruded plus solid solution state, and extruded plus solid solution plus aging state, and the influence of frequency, temperature and kinds of processes on damping capacity are studied as compared with as-received casting state of Mg-12Gd-3Y-0.5Zr.The results are as follows: the microstructures are more uniform and have high mechanical properties near the center of extruded bar, so samples are cut from central region for study in this work; no obvious grain growth are observed after solid solution at 425℃, however, Gd and Y has high solid solubility and more uniform distribution at this temperature, 425℃is thus regarded as the best temperature of solid solution in this work. Strengthen effect of samples increases as aging temperatures increases, where 220℃is the best temperature for aging. The optimum treatments in the present work is 190℃for 2h aging plus 220℃for 10h aging, under which the samples has the highest mechanical properties as 357 Mpa of yield strength, 443 Mpa of ultimate tensile strength, and 2.7 % of elongation to failure. Damping capacity increases as frequency increasing under low- frequency condition and remains the same during 20-150℃. And damping capacity are almost the same of as-extruded and as-casted samples, while there obtains lower damping capacity value in samples after solid solution and aging. Therefore, heat treatments have decrease the damping capacity of Mg-12Gd-3Y-0.5Zr (wt. %) magnesium under low- frequency condition.