摘要
将Zn和Y元素以原子比为6∶1的形式加入AM50合金中,并采用金属型铸造成形,利用OM,SEM,EDS,XRD,热分析法及拉伸实验研究了AM50-x(Zn,Y)(x=0,2,3,4,5,质量分数,%)合金的显微组织、凝固行为及力学性能.结果表明:向AM50合金中按原子比为6∶1的形式加入Zn和Y元素后,组织得到明显细化,组织中并未形成Mg3Zn6Y准晶相,而是形成了颗粒状的Al6YMn6相和细小的Al2Y相,其中Al6YMn6相尺寸随着Zn和Y元素含量的增加而增大;当x≥3时,在组织中b相的周围逐渐形成层片状的F-Mg21(Zn,Al)17相,且其数量逐渐增加.热分析结果表明,F-Mg21(Zn,Al)17相约在354℃通过包晶反应形成,其中a-Mg和b相析出温度随着x的增加而降低.由于Al6YMn6相、Al2Y相和F-Mg21(Zn,Al)17相的形成,使得b相的尺寸减小、数量减少;当x=4时,合金组织最为细小,且合金力学性能达到最优,其抗拉强度、屈服强度和伸长率分别为206.63 MPa,92.50 MPa和10.04%.
As the lightest metallic structural material, magnesium alloys were widely used in automotive, aero- space, electronic equipment and other fields. Among commercial magnesium alloys, AM series were commonly used due to excellent ductility and energy absorption. However, their relatively poor strength greatly restricted their ex- tended use. In order to improve mechanical properties of AM50 alloy, the Zn and Y elements were added into the AM50 alloy in the form of atomic ratio of 6：1 by the permanent mold casting. The microstructure, solidification be- havior and mechanical properties of AM50-x（Zn, Y） （x=0, 2, 3, 4, 5, mass fraction, %） alloys were investigated by OM, SEM, EDS, XRD, thermal analysis and tensile tests. The results indicated that addition of Zn and Y elements with an atomic ratio of 6：1 to AMS0 alloy, the microstructures were obviously refined, and the quasicrystal I-phase （Mg3Zn6Y） cannot form. In addition, the granular Al6YMn6 phase and fine Al2Y phase were formed in the micro- structure, and the size of Al6YMn6 phase increased with increasing the Zn and Y content. The Φ-Mg21（Zn, Al）17 phase with lamellar structure was formed around β phase when x≥3, and its amount increased with increasing the Zn and Y addition. Thermal analysis results show that the Φ-Mg21（Zn, Al）17 phase was formed at 354 ℃ by the peri- tectic reaction, in which the precipitation temperatures of α-Mg and β phase were decreased with the increase of x content. Due to the formation ofAl6YMn6, ALY and Φ-Mg21（Zn, Al）17 phases, the size and amount of the β phase was decreased. For AM50-4（Zn, Y） alloy, the microstructure was greatly refined, and the ultimate tensile strength, yield strength and elongation of the alloy reached to the maximum, 206.63 MPa, 92.50 MPa and 10.04%, respectively.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2016年第9期1115-1122,共8页
Acta Metallurgica Sinica
基金
国家自然科学基金项目51504153
辽宁省自然科学基金项目201602548
辽宁省高校创新团队支持计划项目LT2013004资助~~
关键词
镁合金
AM50
显微组织
热分析
力学性能
magnesium alloy, AM50, microstructure, thermal analysis, mechanical property
