SPS烧结WC-5%Co纳米复合粉硬质合金

采用喷雾干燥、流态化床化学转化法生产的WC-5%Co纳米复合粉为原料,研究了放电等离子体烧结(SPS)对超细硬质合金显微结构和性能的影响,同时对SPS烧结、低压烧结、真空烧结等三种工艺进行了比较。结果表明:采用SPS烧结可以在较低的温度下实现超细硬质合金的固相烧结,使合金快速致密化,当1170℃保温6min、压力为50MPa时合金可以获得最好的力学性能;其显微硬度HV30、抗弯强度、断裂韧性分别为1870、3230MPa、10.96MPa/m1/2。低压烧结可促进颗粒在液相中重排,硬质合金压坯经8MPa、1410℃、保温45min烧结,也可以获得比较好的力学性能;而传统真空烧结,合金孔隙度比较高,晶粒不均匀,性能较差。

Spark Plasma Sintering of Ultrafine WC-5%Co Cemented Carbide Composite Powders

WC-5%Co composite nano-powder produced by spray drying continuous chemical conversion in fluidised technology was used for this study, the microstructure and properties of ultrafine cemented carbide sintered by spark plasma sintering（SPS） were studied, the SPS was compared with pressure sintering and vacuum sintering at the same time. Results show that composite powder was densified in solid state sintering at lower temperature, the best mechanical properties were obtained sintered at 1 170 ℃ for 6 min under 50 MPa, the hardness（HV30）, transverse rupture strength（TRS） and fracture toughness（KIC） were respectively 1 870,3 230 MPa, 10.96 MPa/m^1/2. the better mechanical properties were obtained sintered at 1 410℃ under 80 MPa, the pressure sintering could promote the rearrangement of WC in liquid phase. The cemented carbide sintered in vacuum had poor properties, there were higher ＂ porosity and nonuniform grain in alloy.