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铁基表面碳化钛致密陶瓷层的组织性能与增韧机制

In situ TiC dense particles layer tissue properties andtoughening mechanism on gray cast iron surface

  • 摘要: 利用铸渗复合-热处理工艺在铁基体表面原位制备了致密碳化钛陶瓷增强复合材料,分别研究了复合材料的物相组成、微观组织及细观组织、显微硬度、断裂韧性. 结果表明,钛板中的钛原子和石墨片中溶解析出的碳原子扩散到冶金结合面原位生成了碳化钛致密陶瓷层,且致密陶瓷层与钛板、致密陶瓷层与基体之间结合良好,界面干净. 致密陶瓷层显微硬度平均值为3 027.08 HV0.1,远远大于基体硬度和残余钛板硬度,试样纵截面致密陶瓷层在20 N载荷下在压痕顶端萌生,扩展了裂纹,其断裂韧性为4.5~14.2 MPa·m1/2,远高于一般的陶瓷材料.

     

    Abstract: Dense titanium carbide reinforced iron-based surface composites were prepared via casting-infiltration and heat treatment process. The phase composition, microstructures and microscopic tissue of samples were researched. Meanwhile, the microhardness and fracture toughness were also studied. The results shows: Titanium carbide dense ceramic layer in situ formed by Ti atoms of titanium plate and C atoms dissolved from graphite sheet diffuse into the metallurgical bonding surface, and the bonding interface of dense layer with titanium plate and substrate are good and clean. The average microhardness of dense ceramic layer is 3 027.08 HV0.1, far greater than the residual titanium plate and matrix hardness. With 20 N loads, the dense ceramic layer longitudinal sectional cracks have initiation and propagation on the top of the indentation. The fracture toughness is between 4.5 MPa·m1/2and 14.2 MPa·m1/2, far higher than normal ceramics.

     

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