Microstructure and hardness properties of composite layers fabricated by TIG surface alloying of Ti-5Al-2.5Sn with titanium and graphite mixed powders

In the present research, formation of composite layer by TIG surface melting on Ti-5Al-2.5Sn with titanium and graphite mixed powders, which promptly pre-placed on the substrate was studied. TIG process parameters including current density and travel speed were optimized to produce defect-free layers. The microstructures of layers were investigated by optical microscope and scanning electron microscope (SEM) equipped with an EDS analysis, and the phases were examined by X-ray Diffraction (XRD) analysis. Formation of titanium carbide in the surface layers was confirmed by XRD patterns. The hardness of the surface layer was then evaluated by Vickers microhardness testing machine. The results showed that the hardness of the layers significantly increased from 355 HV0.2 to 1448 HV0.2 for the as-received substrate and composite layers, respectively.

کلیدواژه ها:

TIG alloying ، Ti-5Al-2.5Sn ، Graphite ، Composite layer ، Microhardness