Study On Technique And Mechanism Of Laser Sintering Of Diamond Fine Powders Compact

The sintering technique of diamond fine powders compact by CO2 laser has been researched systematically in the thesis. On the basis of the microanalysis on the combination between diamond fine powders and metallic powder, the permeability between them is introduced in order to guide the choice and design of the system of metallic powder. The influences of laser power and scanning speed on sintering performances are studied to choose and optimize the sintering parameters. The research shows: ①Powder compacts with Ti are oxidized more easily at the non-shield atmosphere. ②Laser power is higher (scanning speed is slower), but it could not surpass a critical value, both qualities of the sintering workpiece and combination of diamond fine powders and metallic element are better. With the parameter of 550W laser powder and 1100mm/min scanning speed, the best sintering workpiece can be obtained. ③At the same processing parameter, surface state and relation with metallic matrix of diamond fine powders are different. Further theoretical research on sintering mechanism has been done on the basis of phenomena observed in the sintering experiments. And thermodynamic behavior of the sintering is discussed in detail. The analysis indicate: ①metallic powder with low melting point will not melt down and sintering will not begin until the laser power reach a critical value. ②Laser sintering is so fast that the melted liquid metal is only linked with high-melting-point powder neighboring. It is the first time to manufacture complicated diamond fine powders tools by laser sintering. The field of laser processing is broadened and traditional sintering means of diamond tools are improved.