The effect of annealing treatment on the microstructures and mechanical properties of cold-sprayed nickel coating  

作　　者：ZHANG Huabing ZHANG Junbao LIANG Yongli SONG Hongwei 

机构地区：[1]Silicon Steel Department,Baoshan Iron ＆ Steel Co. ,Ltd. ,Shanghai 200941 ,China [2]Advanced Technology Division ,Baosteel Research Institute ,Baoshan Iron ＆ Steel Co. ,Ltd. , Shanghai 201900 ,China

出　　处：《Baosteel Technical Research》2009年第2期46-51,共6页宝钢技术研究（英文版）

基　　金：supported by the Shanghai "Qi-Ming-Xing" science and technology foundation for young scientists(No.06QB14032)

摘　　要：The effect of annealing treatment on the microstructures and mechanical properties of cold-sprayed Ni coating was investigated by conducting micro-hardness and tensile tests and using a normal optical microscope （OM） ,a scanning electron microscope （ SEM）, a transmission electron microscope （TEM） and an electron probe X-ray microanalyzer （EPMA）. The results show that following the increase of the annealing temperature ,the micro-hardness of cold-sprayed Ni coating decreases and the elongation after fracture increases, while the tensile strength increases before decreasing. The tensile deformation and fracture behavior change from a typical brittle fracture to a hybrid brittle and ductile fracture, then to a typical ductile failure. It is found that when annealed at an elevated temperature （ e. g. 900℃ ） ,the grains tend to grow abnormally with the oxides spheroidizing and the defects agglomerating at the interfaces, causing the tensile strength reduction of the cold-sprayed nickel coating. It is also pointed out that the tensile strength of the cold-sprayed Ni coating can be significantly improved by the appropriate annealing procedures, but the elongation after fracture cannot be clearly increased because it is difficult to eliminate the main defects in the coating by the following heat treatments.The effect of annealing treatment on the microstructures and mechanical properties of cold-sprayed Ni coating was investigated by conducting micro-hardness and tensile tests and using a normal optical microscope （OM） ,a scanning electron microscope （ SEM）, a transmission electron microscope （TEM） and an electron probe X-ray microanalyzer （EPMA）. The results show that following the increase of the annealing temperature ,the micro-hardness of cold-sprayed Ni coating decreases and the elongation after fracture increases, while the tensile strength increases before decreasing. The tensile deformation and fracture behavior change from a typical brittle fracture to a hybrid brittle and ductile fracture, then to a typical ductile failure. It is found that when annealed at an elevated temperature （ e. g. 900℃ ） ,the grains tend to grow abnormally with the oxides spheroidizing and the defects agglomerating at the interfaces, causing the tensile strength reduction of the cold-sprayed nickel coating. It is also pointed out that the tensile strength of the cold-sprayed Ni coating can be significantly improved by the appropriate annealing procedures, but the elongation after fracture cannot be clearly increased because it is difficult to eliminate the main defects in the coating by the following heat treatments.

关 键 词：cold spray Ni coating annealing treatment microstructure and mechanical property 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TG146.21[金属学及工艺—合金]