烧结方法对Ni-MF/Al_2O_3复相陶瓷力学性能及微观结构影响

Microstructure and Mechanical Properties of Ni-MF/Al_2O_3 Multiphase Ceramic

采用裸烧和石墨埋烧两种烧结方法制备Ni-MF/Al2O3复合材料,研究不同质量的镍(Ni)颗粒对莫来石纤维(MF)增强氧化铝陶瓷复合材料的结构和力学性能影响。采用X射线衍射(XRD)、扫描电子显微镜(SEM)分析复合材料的化合物组分以及Ni掺杂后韧性增加的原理。结果表明:选用石墨埋烧法,当复合材料中加入w(Ni)=15%时,其抗弯强度达731.67 MPa,断裂韧性达9.32 MPa.m1/2,相对密度为96.8%。石墨埋烧试样的抗弯强度、断裂韧性和相对密度优于裸烧的试样;随着Ni质量分数的增加,试样的抗弯强度呈线性下降,断裂韧性呈线性增加,相对密度呈先升高后下降;Ni掺杂复合材料可实现韧性提高;Ni颗粒与MF纤维使复合材料的韧性得以改善。

Ni-MF/Al2O3 composite is fabricated by the traditional sintering technique and the covering sintering method,respectively,and the influence of different mass fractions of nickel on the microstructure and properties of MF/Al2O3 is investigated.By the techniques of XRD and SEM,we analyze the components of the composite and the toughening mechanism of nickel.The results show that when sintered covering with graphite,the flexural strength,fracture toughness and relative density of the composite with Ni 15%wt are 731.67MPa,9.32MPa·m1/2 and 96.8%,respectively,which is better than that of the composite sintered by traditional method;with the increase of the mass fraction of nickel,the flexural strength linearly decreases and the fracture toughness linearly increases,while the relative density of the composite firstly increases and secondly descends.Ni together with MF fiber makes the toughness of the composite improved.