锰合金化对ZA33显微组织和热疲劳性能的影响

Effect of Mn Alloying Process on Microstructure and Thermal Fatigue Property of ZA33 Alloy

用光学显微镜观察合金显微组织和热疲劳裂纹,研究锰合金化对ZA33合金显微组织、力学性能和热疲劳性能的影响。结果表明,加入0.6%的锰可以有效细化ZA33合金组织,热疲劳性能得到明显提高。随着锰加入量的增加,抗拉强度呈现先提高再降低的变化规律,硬度略有增加,而延伸率略有降低。在锰含量为0.6%时合金的强度与塑性配合最佳,此时的综合力学性能最优,并且合金的裂纹长度最短,热疲劳性能最好。当锰含量大于0.6%后,由于合金液中的富锰相在晶界处聚集并长大,产生应力集中,恶化热疲劳性能。

The effects of Mn alloying process on the microstructure,mechanical and thermal fatigue property of ZA33 alloy are investigated by observation of microstructure and thermal fatigue cracks of the alloy with OM. The results show that the grains of ZA33 alloy are effectively refined after the adding of0. 6% Mn and thermal fatigue property is also improved. With the increase of Mn amount,the tensile strength is firstly increased and then decreased,the hardness is slightly increased,and the elongation rate is slightly decreased. When the Mn content is 0. 6%,the best coordination of strength and plasticity is achieved,the mechanical properties are optimial,micro-cracks of the alloy are the shortest,and the best thermal fatigue property is reached. When the Mn content is over 0. 6%,the Mn-rich phases will be gathered and grow up in the grain boundaries,which makes the stress concentrate and then the thermal fatigue performance deteriorate.