Performance of Laser Alloyed Ceramics Reinforced Metal Matrix Composites on TA2 Titanium Alloy

摘要

The NiCoCrAlY-SiC mixed powders was used to improve the wear resistance of a TA2 Ti-alloy surface by means of the laser alloying technique using a CO2 laser. The synthesis of the hard composite layer on TA2 Ti-alloy by laser alloying NiCoCrAlY-SiC pre-placed powders was investigated. Microstructural analysis was conducted using an optical microscope and a high resolution transmission electron microscope (HRTEM) and energy dispersive spectroscopy (EDS). Microhardness was measured with a microsclerometer and the wear characteristics of the laser alloyed layer was studied with a disc wear tester. Experimental results indicated that the amorphous phases were produced in the laser alloyed layer; moreover, with increased laser scanning speed, the microhardness of the laser alloyed layer increases accordingly. When the SiC absorbed enough energy from the laser beam to be melted completely, favouring refinement of laser alloyed layer; however, when SiC did not obtain enough energy, the unmelted SiC bulks were present in such layer. Also, the effect of the variation of the laser scanning speed on the microstructure performance of the laser alloyed layer will be explored in detail.