Ti-47Al-2Cr-2Nb-0.2W合金微观组织对其阻尼性能的影响

Effect of the microstructures of Ti-47Al-2Cr-2Nb-0.2W alloy on damping property

通过金相显微镜(OM)、扫描电镜(SEM)和动态热机械分析仪(DMAQ800)等分析手段研究粉末冶金法制备的Ti-47Al-2Cr-2Nb-0.2W(原子分数,%)合金微观组织对其阻尼性能的影响。研究结果表明:Ti-47Al-2Cr-2Nb-0.2W合金初始组织为近γ组织,其阻尼性能最差,在振幅为100μm时,损耗因子仅为0.007;在1 330℃下保温15 min空冷可获得细小全层片组织,层片晶团的平均尺寸约为200μm,其损耗因子在振幅为100μm时达到0.012。随温度升高或保温时间延长,层片尺寸和晶团尺寸明显增大,合金阻尼性能下降,保温120 min时层片晶团的平均尺寸约为510μm,其损耗因子在振幅为100μm时为0.009。细小全层片的阻尼性能最好,而双态组织的阻尼性能介于近γ组织和细小全层片组织之间。

The effect of the microstructures of Ti-47Al-2Cr-2Nb-0.2W alloy on damping property was investigated using optical microscopy （OM）, scanning electron microscopy （SEM）, DMAQ800 and other analytical tools. The results show that the initial microstructure of Ti-47Al-2Cr-2Nb-0.2W alloy is nearly γ, whose tanδ is only 0.007 when amplitude equals 100, the alloy has the worse damping property relatively. The fine full lamellar microstructure whose lamellar colonies size is approximately 200μm is obtained at 1 330℃for 15min with aircooling （AC）, and it’s tanδreaches 0.012 when amplitude is 100 μm. With increasing heat treatment temperature or holding time, the lamellar colonies size is enlarged obviously, but the damping property decreases, the average lamellar colonies size is approximately 510μm and it’s tanδis 0.009 when holding time is 120 min and amplitude is 100μm. Fine full lamellar microstructure has the best damping property, while duplex microstructure’s damping property is between that of the nearlyγmicrostructure and fine full lamellar microstructure.