Preparation And Properties Of Photocured 3D Printed YG6 Cemented Carbide

WC-based cemented carbide has high modulus,high hardness,wear resistance and medium fracture toughness,making it a leader in cemented carbide and one of the most widely used industrial tool materials.3D printing can make up for the shortcomings of traditional methods that are difficult to prepare some complex structure cemented carbides,and expand its application range.In this paper,the three-dimensional structure cemented carbide was printed by photocuring3D printing,and the cemented carbide was prepared indirectly/directly using inorganic salts and metal powders as raw materials.The printing process,subsequent sintering process and product performance were studied,and the following conclusions were obtained:（1）Using ammonium metatungstate as tungsten source and cobalt acetate as cobalt source,the precursor body was obtained by photocuring printing,and the cemented carbide was obtained by one-step reduction and carbonization.Optimized 3D printing ink formulation:water/acrylic acid ratio is 2.5,ammonium metatungstate dosage is less than 100%of solvent mass,nano-TPO and PEGDA dosage is 2%of solvent mass.（2）The printed precursor was dried to remove the excess moisture and acrylic acid of the precursor,and then post-treated at high temperature.In the process of one-step reduction and carbonization,the carbon sources generated by the decomposition of organic tungsten are carbonized into W₂C and WC in turn.The cemented carbide sintered with Co has complete structure and smooth surface,but there is still a lack of carbon phase Co₃W₁₀C_3.4.（3）In view of the insufficient curing depth of WC powder,a surface modification method is proposed:silane coupling and organic coating.The photocuring thickness of the powder after surface modification can be increased by 200%–300%.The influence mechanism of surface modification on the light curing properties of WC slurry was revealed:1.Surface modification increased the particle size and the diffuse reflection of powder to ultraviolet light,thus improving the light curing properties of WC slurry.2.Changing the light dispersion,there is an organic film on the surface of WC,which reduces the absorption of ultraviolet light by WC powder and improves the adhesion and dispersion between WC powder and resin.3.Reducing the refractive index difference between WC powder and resin increases the photocuring thickness.（4）The effects of solid volume fraction and dispersant on rheological and sedimentation properties of WC slurry were revealed.Optimum formula of 3D printing WC-Co slurry:solid volume fraction 40%,dispersant DEGO 655,adding amount 1.7%of WC powder mass.The degreasing process of 3D printing blank was studied,and a low-speed（0.1-0.5℃/min）degreasing process was proposed.After subsequent degreasing and sintering,the properties of cemented carbide products are as follows.The density is 14.5 g/cm³,the average grain size of WC is 1.2μm,the magnetic value of cobalt is 5.71%,and the hardness HV₃is 1400.46 Figure,9 table,104 references...