陶瓷颗粒增强扩散合金化钢复合材料的微观结构和力学性能

采用传统粉末冶金工艺制备了陶瓷颗粒增强Fe?0.5Mo?1.75Ni?1.5Cu?0.7C扩散合金化钢复合材料，选用的陶瓷颗粒为SiC、TiC和TiB₂。采用光学显微镜和扫描电子显微镜观察了烧结材料微观结构，并对烧结材料的硬度、强度和摩擦磨损性能进行了测试。结果表明，由于SiC和TiB₂与基体的化学相容性好，陶瓷颗粒与基体界面结合良好；由于TiC颗粒具有极高的化学稳定性，TiC颗粒与基体界面结合情况不理想。随着陶瓷相含量（质量分数）的增加，添加SiC和TiC的烧结试样相对密度降低；添加TiB₂的烧结试样相对密度先增加后降低，当添加TiB₂质量分数为0.9%时达到最大值。随着陶瓷含量增加，添加SiC和TiB₂烧结试样的硬度增大，当陶瓷相质量分数超过1.2%时，硬度增加缓慢；添加TiC烧结试样的硬度先增加后降低，当添加TiC质量分数为0.9%时达到最大值。随着陶瓷相含量增加，添加SiC和TiC烧结试样的强度降低，少量添加SiC对强度没有明显损害；添加TiB₂烧结试样的强度先增加后降低，当添加TiB₂质量分数为0.6%时达到最大值（971.7MPa），比基体提高了14.1%以上。添加陶瓷相对烧结钢性能的积极影响依次是TiB₂、SiC和TiC。

Microstructure and mechanical properties of diffusion alloyed steel composites reinforced by ceramic particles

The ceramic particle reinforced Fe?0.5Mo?1.75Ni?1.5Cu?0.7C diffusion alloyed steel composites were prepared by the conventional powder metallurgy techniques, using SiC, TiC, and TiB₂ as the reinforced ceramic particles, respectively. The microstructures of the sintered specimens were observed by the optical microscope and scanning electron microscope, and the hardness, tensile strength, and friction-wear performance were tested systematically. In the results, the interface bonding between the matrix and the ceramic particles is perfect due to the excellent chemical compatibility of SiC and TiB₂ with the matrix; the interface bonding between the matrix and TiC particles is inferior because of the high chemical stability. The relative density of the sintered specimens reinforced by SiC and TiC decreases monotonously with the increase of the ceramic phase mass fraction; while the relative density of the sintered specimens reinforced by TiB₂ increases firstly and then decreases with the increase of TiB₂ mass fraction, and the relative density reaches the maximum value when the TiB₂ mass fraction is 0.9%. The hardness of the sintered specimens reinforced by SiC and TiB₂ increases monotonously with the increase of the ceramic phase mass fraction, and the increased rate becomes gently when the ceramic particle mass fraction exceeds 1.2%; the hardness of the sintered specimens reinforced by TiC increases firstly and then decreases with the increase of TiC mass fraction and reaches the maximum value when the TiC mass fraction is 0.9%. The tensile strength of the sintered specimens reinforced by SiC and TiC decreases monotonously with the increase of the ceramic particle mass fraction, a small amount of SiC addition has no visible impairment on the tensile strength; the tensile strength of the sintered specimens reinforced by TiB₂ increases firstly and then decreases and reaches the maximum value of 971.7 MPa when the TiB₂ mass fraction is 0.6%, which increases by over 14.1% compared with the martrix. The positive effect of the ceramic particles on the performance of the sintered specimens is TiB₂, SiC, TiC in turn.