等离子和激光表面合金化对灰铸铁组织性能的影响  

Effect on Microstructure and Properties of Gray Cast Iron by Plasma and Laser Surface Alloying

作　　者：缪亚锋 郑志镇[1] 李建军[1] 赵航[1] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,湖北武汉430074

出　　处：《热加工工艺》2016年第6期202-205,共4页Hot Working Technology

基　　金：国家科技重大专项(2012ZX04010-081)

摘　　要：采用等离子束和激光表面合金化对灰铸铁表面进行强化。利用三点弯曲试验测试合金化层抗弯性能,采用金相显微镜、显微硬度计、SEM和XRD等仪器对其微观组织、硬度断口形貌和相组成进行分析。研究结果表明:灰铸铁等离子束表面合金化层由奥氏体和莱氏体组成,而激光合金化层几乎全部为奥氏体。在相同功率密度下,采用等离子束表面合金化处理后的合金化层较厚;合金化层的硬度最大值均为次表面;Fe_3C和Cr_7C_3的存在使得等离子束合金化层的硬度比激光合金化层高;等离子束合金化层断裂方式为解理断裂,而激光合金化层为韧性断裂。Plasma and laser surface alloying were used to strengthen the surface of gray cast iron. The three-point bending tests were applied to measure the flexural behavior. The microstructure, hardness, fracture morphology and phase composition of the alloying layers were analyzed by metallographic microscope, microhardness meter, scanning electron microscope （SEM） and X-ray diffractometer （XRD）. The results indicate that plasma alloying layer is composed ofaustenite and ledeburite. The microstructure of laser alloying layer is mainly austenite, and the thickness of plasma alloying layer is thicker than laser alloying layer with the same power density. The maximum microhardness of alloying layer appears at the second-surface layer which has a certain distance to the surface. Because of the existence of Fe3C and Cr7C3 in plasma alloying layer, its microhardness is higher than that of laser alloying layer. The fracture mode of plasma alloying layer is cleavage fracture, but the laser＇s is ductile fracture.

关 键 词：灰铸铁 表面合金化 微观组织 硬度 三点弯曲 

分 类 号：TG156.99[金属学及工艺—热处理] TG143.6[金属学及工艺—金属学]