微波烧结氮化硅基陶瓷刀具及其切削性能研究

发布时间：2018-07-17 09:08

【摘要】：陶瓷刀具由于其良好的耐磨性、出色的耐高温性、抗热震性和化学稳定性,在高速切削领域有着广泛的应用。但传统的陶瓷烧结技术存在着烧结体内部温度不均、烧结效率和能源利用率较低等缺点。本文利用微波烧结技术,通过材料体系设计、增强相的添加和微波烧结工艺的优化制备出性能优良的Si_3N_4基复合陶瓷刀具材料。对优化过的Si_3N_4基复合陶瓷刀具进行切削试验,研究其在不同切削参数下的切削性能,并与商业化陶瓷刀具SG4和硬质合金刀具YS8进行对比。首先研究了微波烧结工艺对Si_3N_4基陶瓷刀具材料的影响。研究结果表明:烧结温度对Si_3N_4基陶瓷刀具影响显著。在1600℃的烧结温度下,材料完全形成了长柱状的β-Si_3N_4晶粒,且综合力学性能最好。保温时间1Omin时材料相变转化率最高,晶粒生长程度也最好。微波烧结的烧结时间相比传统烧结工艺至少缩短三分之二,充分显示了微波烧结的高效、节能的特点。研究了SiC的添加对Si_3N_4基陶瓷材料性能的影响。研究结果表明:当加入SiC的粒度为1OOnm时材料的微观组织最细密、均匀,柱状晶形成比较完全。含量为5wt%的SiC会促进Si_3N_4的充分相变,使得晶粒生长完全,进而提高材料的硬度;产生更多的穿晶断裂模式,从而提高材料的断裂韧性。烧结材料致密度为96.65%、维氏硬度14.46GPa、断裂韧性 7.33MPa·m1/2。研究了Si_3N_4基陶瓷刀具材料连续干式切削淬硬45#钢的切削性能,确定其最佳切削用量为切削速度v=100m/min,进给量f=0.14mm/r,切削深度a_p=0.1mm。在此切削条件下刀具切削距离4000m时达到磨钝标准,稍短于SG4和YS8,但加工表面质量高于两者。刀具磨损机理是磨粒磨损和氧化磨损,也出现了粘结磨损现象。研究了Si_3N_4基陶瓷刀具材料连续干式切削淬硬合金钢40Cr的切削性能,确定其最佳切削用量为切削速度v=100m/min,进给量f=0.1mm/r,切削深度a_p=0.15mm。在此切削条件下刀具切削距离为2500m,比SG4和YS8的短,但加工表面质量比两者略高。刀具磨损机理为磨粒磨损和氧化磨损。
[Abstract]:Ceramic tools are widely used in high speed cutting due to their good wear resistance, excellent high temperature resistance, thermal shock resistance and chemical stability. However, the traditional ceramic sintering technology has some disadvantages, such as uneven temperature, low sintering efficiency and low energy efficiency. In this paper, Si _ 3N _ 4 composite ceramic tool materials with excellent properties are prepared by microwave sintering technology, material system design, reinforcement phase addition and microwave sintering process optimization. The cutting performance of the optimized Si3N4 based composite ceramic tool under different cutting parameters was studied and compared with the commercial ceramic tool SG4 and the cemented carbide tool YS8. The effect of microwave sintering process on SiS _ 3N _ 4 based ceramic tool material was studied. The results show that the sintering temperature has a significant effect on the SiS _ 3N _ 4 ceramic cutting tools. At the sintering temperature of 1600 鈩，

本文编号：2129935