Research On Microwave-enhanced Sintering Preparation Of Metal Matrix-diamond Composite Materials For Superhard Materials

Superhard material products made of metal-based diamond composites are widely used in geological drilling,oil exploration,construction and precision machining.With the development of related industries,the preparation methods and comprehensive properties of metal-based diamond composite materials have been put forward higher requirements.As a new type of energy carrier,microwave exhibits the advantages of overall heating,energy in situ conversion and reduced activation energy during sintering.It is an effective way to optimize the preparation method and improve the performance of composite materials.This work,a typical metal-based diamond composite material was studied,and a new microwave sintering technology with good formulation adaptability was developed.Aiming at the temperature rise characteristics of metal powder in microwave field,the heating law of metal powder in microwave field was obtained.According to the formulation principle of metal-based diamond composites,three types of metal-diamond composites(Fe-Cu based,Fe-Cu prealloyed base and Cu based)were selected.The adaptive microwave sintering parameters was obtained by analyzing the microstructure and mechanical properties of the materials.The optimized sintering process system of pressure sintering showed that the optimum parameters of microwave hot pressing sintering of Fe-Cu base were sintering temperature 850?,sintering time 5 min,hot pressing pressure 25 KN;Fe-Cu prealloyed microwave hot pressing sintering process parameters were The sintering temperature is 840?,the sintering time is 5 min,and the hot pressing pressure is 25 KN.The microwave pressureless sintering process parameters of Cu based diamond composites are sintering temperature of 900?,pressure of 395 MPa,sintering time of 30 min.Compared with conventional sintering,the composite material obtained by microwave sintering has a better holding state for the diamond abrasive,and the prepared composite materials all exhibit better comprehensive mechanical properties(such as bending strength,impact toughness and wear resistance),while microwave sintering has obvious advantages in reducing sintering temperature,shortening sintering time,and homogenizing sintered structure,especially the microwave pressureless sintering,under the premise of ensuring the mechanical properties are equivalent,the total time of pressureless sintering is The reduction of 325 min to 150 min significantly reduced the production cost of the product.