Te、Sb对ZL114A合金T6态微观组织与力学性能的影响

Study on Microstructure and Mechanical Properties of ZL114A Alloy in T6 State Bearing Te and Sb

摘要:

通过在ZL114A合金熔炼过程添加Te、Sb元素完成了硅相变质处理,利用电感耦合法(ICP)测定了材料的化学成分,分别采用差热分析(DSC)、万能试验机、金相显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)与透射电镜(TEM)全面分析了合金在不同T6热处理态下的力学性能、晶界Si相形貌与组织演化规律。结果表明,随着固溶/时效温度的增加,晶界处Te、Sb元素溶入初生α-Al基体内部的数量与密度连续增加,晶界处Al₄(Te,Sb)低熔点共晶相的数量不断减少,520℃～530℃范围内吸热峰峰值连续上升,晶界处Si相组织形貌由针片状、多边形状与长棒状演变为短棒状、椭圆状与球状,球形平均粒径仅为9μm；Si、Mg元素溶入初生α-Al基体的数量与密度、淬火瞬间Si相的固溶过饱和度随之增加。聚乙二醇淬火介质下经545℃固溶20h与170℃时效10h,合金材料平均抗拉强度、屈服强度、延伸率、断面收缩率与维氏硬度高达360MPa、307MPa、10.4%、13.8%与122,断口表面以韧窝断裂为主,伴生少量沿晶断裂带,Mg₂Si强化相平均长度约为224nm。

Abstract:

The silicon modification was prepared by adding Te and Sb elements in the smelting process. The chemical composition of the material was determined by inductively coupled method, the mechanical properties, morphology and microstructural evolution of silicon under different T6 states were analyzed by DSC, OM, SEM, EDS, TEM and Universal testing machine. The results show that the number and density of Te, Sb and Si, Mg elements dissolve in the primary α-Al matrix and the endothermic peak among from 520℃ to 530℃ rises with the increase of the solid solution and aging temperature, together with an increased solution supersaturation of silicon in the quenching moment. Whereas, the quantity of Al₄(Te,Sb) eutectic phase reduces continuously, the morphology of silicon particles change from pin-like, polygonal and long-rod to short-rod like, oval and spherical, the average size is merely 9 μm. The average tensile strength, yield strength, elongation, reduction of area and Vickers hardness after solidifing at 545℃ for 20h and aging at 170℃ for 10h with the polyethylene glycol quenching medium are 360MPa, 307MPa, 10.4%, 13.8% and 122, dimple morphology is the dominated fracture surface, accompanied by some intergranular fracture zone, and the average length of Mg₂Si phase is about 224nm.