挤压Mg-Y-Ni-Co合金的显微组织和力学性能  

Microstructure and mechanical properties of extruded Mg-Y-Ni-Co alloy

作　　者：毕广利[1,2] 满宏生 姜静 李元东[1,2] 蒋春宏 陈体军[1,2] BI Guang-li;MAN Hong-sheng;JIANG Jing;LI Yuan-dong;JIANG Chun-hong;CHEN Ti-jun(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Lanzhou Lanshi Testing Technology Co.,Ltd.,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学材料科学与工程学院,兰州730050 [3]兰州兰石检测技术有限公司,兰州730050

出　　处：《中国有色金属学报》2023年第4期1011-1023,共13页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51961021,52001152)。

摘　　要：采用光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和万能试验机,研究了挤压Mg-2.19Y-0.66Ni-0.76Co(摩尔分数,%)合金板材的显微组织和力学性能。结果表明:铸态合金主要由α-Mg基体、晶内14H-LPSO相、分布在晶界的18R-LPSO、Mg Y(Co,Ni)_(4)及少量弥散的富Y相组成。均匀化过程中合金发生由晶界的18R-LPSO相向晶内的14H-LPSO相的相转变。挤压后合金发生动态再结晶,晶粒显著细化,并形成弱的基面织构,第二相碎化并沿挤压方向分布。拉伸测试结果显示,挤压合金表现出优异的强塑性匹配,其室温的屈服强度(σ_(TYS))、极限抗拉强度(σ_(UTS))和断裂伸长率(ε)分别为277.2 MPa、199.3 MPa和32.77%。该合金表现出良好的强度和塑性平衡(采用极限抗拉强度断裂伸长率的乘积值表达塑性:σ_(UTS)×ε=9.08 GPa·%),其室温下高的拉伸强度主要是由于晶粒细化和LPSO相强化,而良好的延展性主要归因于晶粒细化和织构弱化。The microstructure and mechanical properties of extruded Mg-2.19Y-0.66Ni-0.76Co(mole fraction,%)alloy sheets were investigated at room temperature by optical microscope(OM),scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffractometer(XRD)and tensile testing machine.The results show that the as-cast alloy is mainly composed ofα-Mg matrix,14H-LPSO in the grain interior,18R-LPSO distributed at the grain boundaries,MgY(Co,Ni)_(4),and a small amount of dispersed rich-Y phases.The alloy occurs phase transformation from the 18R-LPSO phase in the grain boundary to the 14H-LPSO phase in the grain interior during homogenization.After extrusion,the grains of the alloy are significantly refined and formed the weak texture owning to dynamic recrystallization during extrusion,and the second phase is fragmented and distributed along the extrusion direction.The tensile test results show that the alloy exhibits excellent strength-plastic balance.The tensile yield strength(σ_(TYS)),ultimate tensile strength(σ_(UTS))and elongation(ԑ)are 277.2 MPa,199.3 MPa and 32.77%at room temperature,respectively.The alloy appears a good strength-ductility balance(σ_(UTS)×ε=9.08 GPa·%).The high tensile strengths of the extruded alloy are mainly attributed to grain refinement and LPSO phase strengthening,while the good ductility are mainly due to grain refinement and texture weakening.

关 键 词：挤压Mg-Y-Ni-Co合金 LPSO相 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]