發(fā)布時(shí)間：2018-07-17 09:08

【摘要】：陶瓷刀具由于其良好的耐磨性、出色的耐高溫性、抗熱震性和化學(xué)穩(wěn)定性,在高速切削領(lǐng)域有著廣泛的應(yīng)用。但傳統(tǒng)的陶瓷燒結(jié)技術(shù)存在著燒結(jié)體內(nèi)部溫度不均、燒結(jié)效率和能源利用率較低等缺點(diǎn)。本文利用微波燒結(jié)技術(shù),通過(guò)材料體系設(shè)計(jì)、增強(qiáng)相的添加和微波燒結(jié)工藝的優(yōu)化制備出性能優(yōu)良的Si_3N_4基復(fù)合陶瓷刀具材料。對(duì)優(yōu)化過(guò)的Si_3N_4基復(fù)合陶瓷刀具進(jìn)行切削試驗(yàn),研究其在不同切削參數(shù)下的切削性能,并與商業(yè)化陶瓷刀具SG4和硬質(zhì)合金刀具YS8進(jìn)行對(duì)比。首先研究了微波燒結(jié)工藝對(duì)Si_3N_4基陶瓷刀具材料的影響。研究結(jié)果表明:燒結(jié)溫度對(duì)Si_3N_4基陶瓷刀具影響顯著。在1600℃的燒結(jié)溫度下,材料完全形成了長(zhǎng)柱狀的β-Si_3N_4晶粒,且綜合力學(xué)性能最好。保溫時(shí)間1Omin時(shí)材料相變轉(zhuǎn)化率最高,晶粒生長(zhǎng)程度也最好。微波燒結(jié)的燒結(jié)時(shí)間相比傳統(tǒng)燒結(jié)工藝至少縮短三分之二,充分顯示了微波燒結(jié)的高效、節(jié)能的特點(diǎn)。研究了SiC的添加對(duì)Si_3N_4基陶瓷材料性能的影響。研究結(jié)果表明:當(dāng)加入SiC的粒度為1OOnm時(shí)材料的微觀組織最細(xì)密、均勻,柱狀晶形成比較完全。含量為5wt%的SiC會(huì)促進(jìn)Si_3N_4的充分相變,使得晶粒生長(zhǎng)完全,進(jìn)而提高材料的硬度;產(chǎn)生更多的穿晶斷裂模式,從而提高材料的斷裂韌性。燒結(jié)材料致密度為96.65%、維氏硬度14.46GPa、斷裂韌性 7.33MPa·m1/2。研究了Si_3N_4基陶瓷刀具材料連續(xù)干式切削淬硬45#鋼的切削性能,確定其最佳切削用量為切削速度v=100m/min,進(jìn)給量f=0.14mm/r,切削深度a_p=0.1mm。在此切削條件下刀具切削距離4000m時(shí)達(dá)到磨鈍標(biāo)準(zhǔn),稍短于SG4和YS8,但加工表面質(zhì)量高于兩者。刀具磨損機(jī)理是磨粒磨損和氧化磨損,也出現(xiàn)了粘結(jié)磨損現(xiàn)象。研究了Si_3N_4基陶瓷刀具材料連續(xù)干式切削淬硬合金鋼40Cr的切削性能,確定其最佳切削用量為切削速度v=100m/min,進(jìn)給量f=0.1mm/r,切削深度a_p=0.15mm。在此切削條件下刀具切削距離為2500m,比SG4和YS8的短,但加工表面質(zhì)量比兩者略高。刀具磨損機(jī)理為磨粒磨損和氧化磨損。
[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，

本文編號(hào)：2129935