Directional growth whisker reinforced Ti-base composites fabricated by laser cladding
New type Ti-base composite coatings with in-situ synthesized directional growth whiskers were fabricated successfully from a precursor mixture of titanium alloy and B4C powders by laser cladding. The typical microstructures, formation mechanism and properties of the reinforced composite coatings were experimentally studied for the purpose of developing a novelty hard facing coating of titanium alloy. The results show that, there are two typical microstructures obtained in the composite coatings, i.e. the equiaxial composite structures and the columnar composite structures. The novel and interesting TiB whiskers, namely the directional growth TiB whiskers, are founded in the columnar composite structure zones. These TiB whiskers show uniform growth directions and display the characteristics of large slenderness ratio. The lengths of the whiskers are in the range of 10-30 μm, but the diameters are of extremely fine size in the nanometer range. The microhardness of the coating are in the range of 430-520 HV and are about 150 HV higher than that of the substrate, which implies that these composite coatings are effectively reinforced by in situ synthesized TiB phases. The analysis shows that, the solidification velocity R, temperature gradient G and direction of heat flow were the key factors to determine what kind of whiskers can be obtained.
Hardfacing coating Laser cladding Directional growth Titanium alloy In-situ reaction
Wei-fu Wang Liang-sheng Jin Fengqiu Sun
College ofMechanical engineering,Zhejiang University ofTechnology,Hangzhou 310014,China Key Laborato College ofMechanical engineering,Zhejiang University ofTechnology,Hangzhou 310014,China Key Laborato School ofscience,Northeastern University,Shenyang 110004,China
国际会议
北京
英文
566-571
2012-10-23（万方平台首次上网日期，不代表论文的发表时间）