金属间化合物MoSi_(2)协同SiC晶须增韧Si_(3)N_(4)陶瓷刀具的制备及切削性能

Preparation and Cutting Performance of Si_(3)N_(4) Ceramic Tool Toughened by Intermetallic Compound MoSi_(2) and SiC Whisker

为进一步提高Si_(3)N_(4)陶瓷刀具的强度和韧性,克服单一增韧方式以及金属粘结剂增韧的局限性,本工作利用金属间化合物协同晶须对其增韧补强,将MoSi_(2)颗粒和SiC晶须添加到Si_(3)N_(4)陶瓷基体中,制备出Si_(3)N_(4)/MoSi_(2)/SiC_(w)(SMC)复合陶瓷刀具材料。结果表明:SiC晶须的加入可以有效提高Si_(3)N_(4)陶瓷的断裂韧性,MoSi_(2)的加入可以显著提升Si_(3)N_(4)陶瓷的抗弯强度。连续干切削45#淬火钢时,相较于商用刀具YBC251,SMC复合陶瓷刀具的寿命及切削稳定性提升显著。其中,添加了SiC晶须的SMC3(MoSi_(2)10%(未作特别说明时均为质量分数),SiC_(w)10%)及SMC2(MoSi_(2)0%,SiC_(w)10%)刀具的寿命均比未添加SiC_(w)的SMC1(MoSi_(2)10%,SiC_(w)0%)更长。随着切削深度的增加,未添加MoSi_(2)的SMC2易出现崩刃现象,切削稳定性不如协同增韧的SMC3。

In order to further improve the strength and toughness of Si_(3)N_(4) ceramic tool,overcome the limitations of single toughening method and metal binder toughening,MoSi_(2) particles and SiC_(w)hiskers were added to the Si_(3)N_(4) ceramic matrix to prepare Si_(3)N_(4)/MoSi_(2)/SiC_(w)(SMC)compo-site ceramic tool material by toughening and reinforcing them with intermetallic compounds and whiskers.The results show that the addition of SiC_(w)hisker can effectively improve the fracture toughness of Si_(3)N_(4) ceramics,and the addition of MoSi_(2) can significantly improve the bending strength of Si_(3)N_(4) ceramics.In continuous dry cutting of 45#quenched steel,the tool life and cutting reliability of SMC composite ceramic tool are significantly improved compared with commercial tool YBC251.Among them,the tool life of SMC3(MoSi_(2)10wt%,SiC_(w) 10wt%)and SMC2(MoSi_(2)0wt%,SiC_(w) 10wt%)with SiC_(w)hisker is better than that of SMC1(MoSi_(2)10wt%,SiC_(w) 0wt%)without SiC_(w).With the increase of cutting depth,SMC2 without MoSi_(2) is prone to chipping,and the cutting reliability is not as good as SMC3 with synergistic toughening.