Fe-Cr基等离子熔覆层的相结构特征

Phase Structure Characteristic of Fe-Cr-Based Cladding Layer Prepared by Plasma Beam

为了提高钢铁材料表面的硬度和耐磨性,用弧光等离子体在45#钢表面制备了Fe-Cr基熔覆层.根据热力学和动力学原理对相的形成进行了分析,用X射线衍射仪、能谱、透射电镜对熔覆层的晶相与非晶相及其相界面结构进行了研究.结果表明:熔覆层中晶相与非晶相并存,非晶相中含有较多的过渡族和类金属元素,如Si,Cr等;晶相由A,F,M23C6,M7C3等相组成,且[211]A//[211]M23C6,(■11)A//(■11)M23C6,(0■l)A//(0■1)M23C6,即A与M23C6保持共格关系,而[111]F//[321]M23C6,(■11)F//(1■■)M23C6,即F与M23C6保持位向平行关系,晶相晶粒显著细化,共晶组织中的奥氏体体晶粒达到200 nm,铁素体尺寸约为70 nm.熔覆层的显微硬度为HV0.2650-750.熔覆层的组织属非平衡组织,有利于提高其硬度.

Hardness and wear resistance of steel were improved using a Fe-Cr-based cladding layer onto steel-45 by arc plasma beam. The formation of new phases of the layer was described by dynamics and thermodynamics. The crystal and amorphous phases were studied by means of X-ray diffractometer （XRD）, and transmission electron microscopy （TEM） equipped with energy-dispersive X-ray spectrometer（TEM-EDX）. The results show that both crystal phase and amorphous phase exist in the cladding layer. The amorphous phase contains significantly transition subgroup and submetallic elements,such as Si, Cr. The crystal phase consists of A,F, Me 23C6 and M7 C3, in which there are relationship of [211] A// [21-] M23C6, （1^-11）A// （1^-11）M23C6 and （01^-1）A//（01^-1）M23C6 ,which means A and M23C6 retains a coherence relation. The relation of [111] F// [321]M23C6 and （1^-01）F//（11^-1^-）M23c6 indicates the orientation of the F and M 23C6keeps a parallel relationship. The grains of crystal phases are obviously refined and the grain size of austenite in eutectic structure reached to 200nm,the size of ferrite is 70 nm. The microhardness of the cladding layer is HV0.2650-750. It is clearly that the hardness of the cladding layer benefit from improving the non-equilibrium microstructures.