MICROSTRUCTRUAL CHARACTERIZATION AND EVOLUTION OF LASER CLAD Fe-BASED ALLOYS
WU Xiaolei; CHEN Guangnan(Institute of Mechanics; The Chinese Academy of Sciences; Beijing 100080)Correspondent: WU Xiaolei;Tel:(010)62547527; Fax: (010) 62561284; E-mail:xlwu@cc5.imech.ac.cn
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WU Xiaolei; CHEN Guangnan(Institute of Mechanics; The Chinese Academy of Sciences; Beijing 100080)Correspondent: WU Xiaolei;Tel:(010)62547527; Fax: (010) 62561284; E-mail:xlwu@cc5.imech.ac.cn. MICROSTRUCTRUAL CHARACTERIZATION AND EVOLUTION OF LASER CLAD Fe-BASED ALLOYS. Acta Metall Sin, 1998, 34(10): 1033-1038.
Abstract In site synthesis of high toughness wear resistance coating alloy Fe-Cr-W-Ni-C(mass ratio are 10: 5: 1: 1: 1) by laser cladding was investigated by SEM and ATEM.Hypo-and hyper-eutectic microstructures, i.e., γ+(γ+M7C3) and M7C3+(γ+M7C3) are obtained while there are competition and selection of the primary phase. The γ-austenite ismetastabe phase with extended solid solution of alloying elements and a great deal of struc structures. There appear various morphologies of eutectic carbide, such as lamellar, honeycomb,herringbone, and network. During high temperature aging, the precipitation of M23C6 and M2Ccarbides from austenite and in site transformations of M7C3 →M23C6 and M7C3 → M6C areobserved in hypo-and hyper-eutectic ndcrostructures respectively. Based on the experimentalresults, transformation mechanism during rapid solidification and thermal aging are proposed.Two microstructures have evidently secondary hardening and the corresponding peak temperatures and peak microhardnesses (HV0.2) are 923 K, 1050 and 963 K, 1250 respectively.
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