Microstructure and properties of as-cast Cu-Cr-Zr alloys with lanthanum addition  

作　　者：Jilin Li Lili Chang Shengli Li Xinde Zhu Zhongxin An 

机构地区：[1]Department of Material Science and Engineering,Shandong University,Jinan 250061,China [2]Zhengzhou Yutong Bus Co.Ltd.,Zhengzhou 450061,China

出　　处：《Journal of Rare Earths》2018年第4期424-429,共6页稀土学报（英文版）

基　　金：Project supported by the Fund of Independent Innovation in Shandong Province(2013CXB60201);the Science and Technology Development Project of Shandong Province(2014GGX102003);the Independent Innovation and Achievements Transformation Special Project of Shandong Province(2014CGZH0102);the Fundamental Research Funds of Shandong University(2016JC016)

摘　　要：Cu-0.45 Cr-0.2 Zr-xLa（x = 0-0.48） alloys were prepared by vacuum casting. The effects of La addition and orientation on the microstructure and properties of the as-cast alloy were investigated by an optical microscope, a scanning electron microscope with an energy dispersive X-ray spectrometer, a tensile testing machine and an electrical conductivity tester. The result shows that the addition of La significantly refines the columnar grainsize and decreases the secondary dendrite arm spacing. Trace addition of La improves the room temperature ultimate tensile strength,elongation and electrical conductivity mainly by purifying during melting and casting. The ultimate tensile strength, elongation and electrical conductivity significantly decrease with the increase of La content due to formation of coarse particles and oxides, which severely harm the performance of the Cu-0.45 Cr-0.2 Zr-xLa alloys. The Cu-0.45 Cr-0.2 Zr-0.13 La alloy possesses a good combination of room temperature ultimate tensile strength, elongation and electrical conductivity. In addition, room temperature ultimate tensile strength and electrical conductivity along transverse direction of the ingot are higher than that along longitudinal direction,which is mainly ascribed to different distribution of grain boundary and grain orientation.Cu-0.45 Cr-0.2 Zr-xLa（x = 0-0.48） alloys were prepared by vacuum casting. The effects of La addition and orientation on the microstructure and properties of the as-cast alloy were investigated by an optical microscope, a scanning electron microscope with an energy dispersive X-ray spectrometer, a tensile testing machine and an electrical conductivity tester. The result shows that the addition of La significantly refines the columnar grainsize and decreases the secondary dendrite arm spacing. Trace addition of La improves the room temperature ultimate tensile strength,elongation and electrical conductivity mainly by purifying during melting and casting. The ultimate tensile strength, elongation and electrical conductivity significantly decrease with the increase of La content due to formation of coarse particles and oxides, which severely harm the performance of the Cu-0.45 Cr-0.2 Zr-xLa alloys. The Cu-0.45 Cr-0.2 Zr-0.13 La alloy possesses a good combination of room temperature ultimate tensile strength, elongation and electrical conductivity. In addition, room temperature ultimate tensile strength and electrical conductivity along transverse direction of the ingot are higher than that along longitudinal direction,which is mainly ascribed to different distribution of grain boundary and grain orientation.

关 键 词：La Cu-Cr-Zr alloy Orientation Ultimate tensile strength Electrical conductivity Rare earths 

分 类 号：TG146.11[一般工业技术—材料科学与工程] TG291[金属学及工艺—金属材料]