微波烧结温度对WC钢结硬质合金组织性能的影响

Effect of microwave sintering temperature on microstructure and properties of WC steel-bonded cemented carbide

以WC颗粒为增强相,铁粉为基体,通过球磨、压制成型,微波烧结制备WC钢结硬质合金。结果表明:随着烧结温度的升高,硬质合金相对密度、显微硬度和抗弯强度均先升高后下降,在1280℃时达到最高值,即相对密度、显微硬度和抗弯强度分别达到94.85%、544 HV和847.37 MPa。1280℃烧结为液相烧结,烧结过程中WC和Fe发生相变,产生新的增强相Fe2W2C,新相以颗粒的形式存在,弥散分布在钢的基体中,对材料的性能起到强化作用。微波烧结比真空烧结温度更低,时间更短,力学性能更好。

WC steel-bonded cemented carbide was prepared by ball milling,press-shaping and microwave sintering with WC as reinforcement phase and iron powder as matrix and its microstructure and properties were examined.The results show that the relative density,microhardness and the bending strength of the steel-bonded cemented carbide increase with the increasing sintering temperature,and reach the maximum values at 1280 ℃,which is 94.85%,544 HV and 847.37 MPa,respectively,and then decrease.It is a liquid phase sintering process when the sintering temperature reaches to 1280 ℃,and chemical reactions occur between the WC and Fe during the sintering process forming a new Fe2W2C phase,of product which is evenly dispersed in the steel matrix and strengthens the material.The microwave sintering possesses the virtues of lower sintering temperature,shorter sintering time and better mechanical properties of product for preparation of WC steel-bonded cemented carbide compared with vacuum sintering.