钛对ZA27合金组织和热疲劳性能的影响

Effect of Ti on the Microstructure and Thermal Fatigue Property of ZA27 Alloy

研究了钛变质处理对ZA27合金的组织和热疲劳性能的影响。通过光学显微镜和扫描电镜观察试样的显微组织和热疲劳裂纹形貌,分析钛的变质机理和合金热疲劳损伤机制。结果表明:经钛变质处理后,ZA27的组织明显细化,初生α-A1相由粗大的树枝晶变为细小的花瓣状枝晶。合金塑性、韧性有较大幅度的提高,从而提高了其热疲劳性能。当Ti的添加量为0.3%时,ZA27合金热疲劳性能最好。

The effect of Ti modification on mierostructure and thermal fatigue property of ZA27 alloy is discussed in this paper. The samples＇ microstructure and morphologies of cracks caused by thermal fa tigue are examined by optical microscopy （OM） and scanning electron microscopy （SEM）, and mecha nism of Ti modification and thermal fatigue damage are analyzed. The results show that after Ti modifica tion, the grains are obviously refined and primary a-A1 phases are found to vary from thick dendrite to fine petalshaped dendrite. The plasticity and toughness of ZA27 are significantly increased, which re suits in the improvement of the thermal fatigue property. With a Ti addition at 0.3%, ZA27 exhibits the best thermal fatigue property.