等离子熔覆原位自生NbC/高熵合金显微组织研究

Microstructure Characterization of in situ NbC/High Entropy Alloys by Plasma Cladding

摘要:

采用等离子熔覆技术在Q235钢基体上原位制备了NbC增强的CoCrCuFeNiMn(NbC)x(x=0, 0.05, 0.1, 0.2, 0.3, 0.4)高熵合金熔覆层，并研究了熔覆层的相组成、显微组织以及显微硬度。结果表明，C和Nb的加入并没有引起熔覆层物相的复杂化，物相由fcc1相、fcc2相和NbC相组成。NbC大多偏聚于基体的树枝晶间，少量在树枝晶内析出。NbC的形态与其含量有关，当x较小时，NbC呈颗粒状；当x较大时，NbC呈颗粒状、长条状以及十字枝晶状。原位自生高熵合金复合材料的硬度较基体合金有了明显提高，在一定范围内(x=0~0.4)，熔覆层显微硬度随增强相含量的升高而增加

Abstract:

In situ NbC reinforced CoCrCuFeNiMn(NbC)x (x=0, 0.05, 0.1, 0.2, 0.3, 0.4) high entropy alloys were prepared by plasma cladding on the Q235 steel. The phase constitution, microstructure and microhardness of the cladding layer were investigated. The results show that C and Nb addition doesn’t cause complex phase and the diffraction peaks are composed of fcc1, fcc2 and NbC phase. Most of the NbC is deposited in the interdendrite and a few of them is dendrite. The shape of NbC is related to its content. When x is small, NbC is granular. When x is large, NbC is granular, strip and cross dendritic. Compared with that of the matrix, the hardness of in situ high entropy alloy matrix composite is significantly improved. The hardness of the cladding layer is increased with more NbC in a certain range (x=0~0.4)