激光金属沉积制备TiC/316L复合材料的组织及力学性能研究

Microstructure and tensile properties of TiC/316L composites fabricated by laser metal deposition

  • 摘要: 激光金属沉积(LMD)技术可同时实现输送粉末和聚焦激光能量,材料成形率高,能够显著提升材料性能和降低制造成本,具有广泛的应用前景。采用LMD技术制备TiC含量为0%、0.5%、1%和2%的TiC/316L不锈钢复合材料,研究了增强体含量对复合材料组织和力学性能的影响。结果表明:通过金相技术观察样品微观结构发现,熔池形貌呈鱼鳞状形貌,中心区域主要为等轴晶粒,熔池边缘区域主要以柱状晶粒为主,相邻熔池之间的柱状晶粒呈外延生长关系,等轴晶粒尺寸分布在10~50μm,而大多数柱状晶粒尺寸超过100μm。随着TiC颗粒含量的增加,复合材料的抗拉强度显著提升,当添加量达到1%时,试样的抗拉强度由623MPa提高至679MPa,且保持30.42%的良好伸长率;然而,当添加量增至2%时,伸长率下降至5.1%,组织中出现了TiC颗粒的团聚现象。

     

    Abstract: Laser Metal Deposition(LMD) technology allows for simultaneous powder delivery and focused laser energy application, resulting in high material forming efficiency. This approach enhances material properties,reduces manufacturing costs, and shows wide application prospects. TiC/316L stainless steel composites with reinforcement contents of 0%, 0.5%, 1%, and 2% were fabricated using LMD technology to investigate the effects of reinforcement content on the microstructure and mechanical properties. Metallographic analysis revealed a fishscale morphology in the melt pool. Equiaxed grains dominated the central region, while columnar grains were prevalent at the edges. Columnar grains between adjacent melt pools exhibited epitaxial growth, with equiaxed grain sizes ranging from 10μm to 50μm, and most columnar grains exceeding 100μm. With increasing TiC content, the tensile strength of the composites improved significantly. At 1% TiC, the tensile strength rose from 623MPa to 679MPa,maintaining an elongation of 30.42%. However, at 2% TiC, the elongation dropped to 5.1%, with agglomeration of TiC particles observed in the microstructure.

     

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