摘要
文中在柱塞表面激光熔覆制备高硬度铁基涂层,采用SEM,XRD,EPMA和TEM等手段研究熔覆层组织特征及耐磨性,阐述其强韧化机理.结果表明,激光熔覆铁基合金涂层成形良好,无裂纹及气孔等缺陷,熔覆层与基体呈冶金结合,组织由(Ni,Fe)固溶体、(Cr,Fe)23C6碳化物和少量孪晶马氏体组成.铁基熔覆层的强化机制主要有细晶强化、固溶强化、弥散强化以及马氏体强化;熔覆层内(Ni,Fe)固溶体及细晶强化的综合作用,保证了高硬度铁基涂层的韧性.铁基熔覆层显微硬度较45钢提高4倍,最大值HHV0.2=850 GPa;熔覆层耐磨性明显高于45钢,45钢表面出现大面积疲劳剥落,铁基熔覆层磨损面平整,磨痕很浅且少,磨损机制为轻微的磨粒磨损.
Iron-based coating with high hardness are prepared on the plunger surface by laser cladding technology,and the structure characteristic and wear resistance are studied by means of SEM,XRD,EPMA and TEM,and then the strengthening and toughening mechanism is presented.The results show that the laser clad Fe-based coating has good forming without cracks and pores,as well as metallurgical bonding with the matrix,which composed of(Ni,Fe) solid solution,(Cr,Fe)23C6carbides and a little twin martensite.The strengthening and toughening mechanism is grains refinement, solid solution strengthening,dispersion strengthening and martensite strengthening.The combined effects of(Ni,Fe) solid solution and refined grains ensure the toughness of Fe-based coating.The microhardness of the coating is 4 times higher than the one of 45steel,with the maximum value of 850HV0.2.The resistance of laser clad coating is also higher than the one of 45 steel,and the worn surface of 45# steel is fatigue flake,which of clad coating is smooth,and the scratch is shallow,and the wear mechanism is abrasive wear.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2014年第2期19-22,114,共4页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(51179202)
中央高校基本科研业务费专项资金(13CX02073A)
国家高新技术863计划项目(2012AA09A203)
山东省自主创新计划(2012CX80101)
关键词
柱塞
激光熔覆
铁基涂层
耐磨性
强韧化机理
plunger
laser cladding
iron-based coating
wear resistance
strengthening and toughening mechanism
