N_(2)分压烧结时间对超细晶粒Ti(C,N)基金属陶瓷组织和力学性能的影响  

Effect of N_(2) Partial-Pressure Sintering Time on Ultrafine-Grained Ti(C,N)-Based Cermets

作　　者：刘云鹏 余海洲 刘文俊 曹攀 Liu Yunpeng;Yu Haizhou;Liu Wenjun;Cao Pan(College of Materials and Chemical Engineering,China Three Gorges University,Yichang Hubei 443002,China)

机构地区：[1]三峡大学材料与化工学院,湖北宜昌443002

出　　处：《硬质合金》2024年第1期37-42,共6页Cemented Carbides

基　　金：国家自然科学基金资助项目(No.51304124)。

摘　　要：针对真空烧结制备超细晶粒Ti(C,N)基金属陶瓷时,烧结体的易脱氮和N的分解问题,通过在液相保温阶段1450℃通入130 Pa氮气,采用分压烧结制备了超细晶粒Ti(C,N)基金属陶瓷,研究了氮气分压烧结时间对金属陶瓷显微组织和力学性能的影响。实验结果表明,氮气分压烧结能提升试样内部组织均匀性。在氮气氛的影响下,试样最外层会形成富Ni层,材料的近表层形成TiN层。分压刚开始,试样最外层只有富Ni层,随分压时间的增加,近表层组织中黑芯相在氮气氛影响下发生溶解,黑芯相尺寸减小,环形相尺寸增加,直至黑芯相逐渐消失,形成富Ti的(Ti,W)(C,N)固溶体,固溶体通过合并长大的方式形成固溶体层,随分压时间增加,富钛的固溶体与N反应在试样近表层形成TiN层。分压烧结时间达40 min时试样的综合力学性能最佳,其抗弯强度增加了20%,达到2350 MPa;维氏硬度增加了13.9%,达到1635HV30;断裂韧性提升不明显。In view of the easy denitrification of the sintered body and the decomposition of N during the preparation of ultrafine-grained Ti(C,N)-based cermets by vacuum sintering,ultrafine-grained Ti(C,N)-based cermets are prepared by partial-pressure sintering with 130 Pa of nitrogen at 1450°C during the holding stage of the liquid phase,and the influence of the time of partial-pressure sintering under nitrogen on the microstructures and mechanical properties of cermets is investigated.The experimental results show that partial-pressure sintering under nitrogen can improve the uniformity of the internal structure of the sample.Under the influence of nitrogen,a Ni-rich layer will be formed in the outermost layer of the sample,and a TiN layer will be formed in the near-surface layer of the material.At the beginning of the partial pressure,the outermost layer of the sample is only the Ni-rich layer.With the increase in the partial pressure time,the black core phase in the near-surface layer of the organization dissolves under the influence of nitrogen,and the size of the black core phase decreases.The size of the annular phase increases until the black core phase gradually disappears,forming a Ti-rich(Ti,W)(C,N)solid solution,which is formed into the solid solution layer by merging the grown solid solution,As the partialpressure time increases,the titanium-rich solid solution reacts with N to form a TiN layer in the near-surface layer of the sample.The comprehensive mechanical properties of the sample are the best when the partial-pressure sintering time reaches 40 min,and its bending strength increases by 20%to 2350 MPa.The Vickers hardness increases by 13.9%to 1635 HV30,and the fracture toughness is not significantly improved.

关 键 词：TI(C N)基金属陶瓷 氮气分压烧结 显微组织 力学性能 氮化层 

分 类 号：TG148[一般工业技术—材料科学与工程]