初始成分对梯度硬质合金微观组织及脱β层厚度的影响  

Effect of starting composition on microstructure and thickness of cubic carbide free layer in graded cemented carbides

作　　者：史留勇[1,2] 刘义敏[1] 张守全 黄继华[1] 赵兴科[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]海南大学机电工程学院,海口570228 [3]厦门金鹭特种合金有限公司,厦门361006

出　　处：《中国有色金属学报》2012年第7期1984-1990,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家"十一五"科技支撑计划资助项目(2007BAE05B02)

摘　　要：采用普通市售中颗粒Ti(C,N)粉末,以一步烧结法制备脱β层梯度硬质合金;利用显微组织分析和图像分析等手段,研究合金初始成分对其微观组织及脱β层厚度的影响规律。结果表明:当Ti(C,N)含量低于1.6%(质量分数)时,随着Ti(C,N)含量的增加,脱β层厚度明显增大,而当Ti(C,N)含量超过1.6%时,脱β层厚度呈缓慢缩小的趋势;随着钴含量的增加,脱β层的厚度迅速增大,但当钴含量达到10%(质量分数)左右时,在脱β层与芯部的界面处钴相聚集现象严重;总碳含量为6.51%(质量分数)的合金中WC晶粒度较大且呈规则的多边形,在1 450℃、2 h梯度烧结工艺下制备的脱β层厚度可达38μm左右,而总碳含量为6.23%的合金中WC晶粒度较小且呈等轴化趋势,同时脱β层的厚度仅为17μm左右。The graded cemented carbides with cubic carbide free layer（CCFL） were fabricated by one-step sintering procedure using Ti（C,N） powder with medium particle size as the raw material,and the effect of starting composition on the microstructure and thickness of CCFL was discussed in detail by scanning electron microscopy and soft Image Tool.The results show that,the thickness of CCFL increases gradually with the increase of Ti（C,N） content when it is lower than 1.6%（mass fraction）,whereas the thickness of CCFL decreases slightly with the increase of Ti（C,N） content when it exceeds 1.6%.The thickness of CCFL increases rapidly with the increase of Co content,whereas the Co phases are inclined to aggregate in the border between CCFL and core zone when the cobalt content reaches 10%（mass fraction）.The WC particles in alloy with total carbon content of 6.51%（mass fraction） are larger in size and show regular polygon usually,the depth of CCFL can reach about 38 μm under the graded sintering process of 1 450 ℃ and 2 h;while in the alloy with total carbon content 6.23%,the WC particles are smaller in size and tend to be spheroidal shape,and the depth of CCFL is only about 17 μm under the same sintering procedure.

关 键 词：梯度硬质合金 TI(C N) 初始成分 脱β层 微观组织 

分 类 号：TF125.3[冶金工程—粉末冶金] TG135.5[冶金工程—冶金物理化学]