摘要
以化学纯镍粉、钛粉、铝粉、石墨粉为原料,采用燃烧合成方法制备了TiC/Ni3Al含孔预制件,用无压熔渗法制备了TiC/Ni3Al复合材料。对TiC/Ni3Al复合材料的微观组织、硬度和断裂韧性进行了研究并采用XRD和SEM分析了复合材料的相组成、微观结构、断口形貌。采用压痕法计算了TiC/Ni3Al复合材料的断裂韧性。试验结果表明:无压熔渗法是制备致密的TiC/Ni3Al复合材料的有效方法。在完成渗透获得致密组织的前提下,渗透温度和渗透时间对TiC/Ni3Al复合材料的硬度及断裂韧性无显著影响。渗透后复合材料的组成相主要为Ni3Al和TiC两相,Ni3Al相和TiC颗粒结合良好。本文制备的Ni3Al/TiC复合材料的维氏硬度随TiC体积分数的增加而增加,TiC含量分别为70%和80%时,复合材料的维氏硬度平均值分别为569.6(Hv)和610.8(Hv)。复合材料的断裂韧性最高达到了10.5MPa.m1/2,TiC颗粒和Ni3Al界面的分离是复合材料断裂过程中存在的主要失效形式。断裂过程中Ni3Al可以有效地吸收裂纹扩展能量,阻止了裂纹的直线扩展,使裂纹扩展方向发生偏转,大大增加了材料的断裂韧性。
In this paper,chemical pure nickel powder,titanium powder,aluminum powder,graphite powder as raw material,TiC/Ni3Al porous performs were prepared by self-propagating high temperature synthesis method(SHS),and pressureless melt infiltration method was used to preparing TiC/Ni3Al composites.The microstructure,hardness and fracture toughness of TiC/Ni3Al composites prepared by pressureless melt infiltration were studied.Phase composition、microstructure and fracture surface of composites were analyzed by using of XRD and SEM.Indentation method used to calculate the fracture toughness of composites.The results show pressureless melt infiltration is the effective way to prepare dense TiC/Ni3Al composites.Add the proper amount of CeF3 can greatly reduce the infiltration time.There are only Ni3Al and TiC two-phase in composites after infiltration and a good combination between Ni3Al phase and TiC particles.In this paper,Vickers hardness of Ni3Al/TiC composites is promoted with increasing the TiC volume fraction,when the content of TiC is 70% and 80%,the average Vickers hardness of composites is 569.6(Hv)and 610.8(Hv),respectively.The maximum fracture toughness is 10.5 MPa·m1/2.In the process of composites fracture,the main failure form is interface separation of TiC particles and Ni3Al.Crack propagation energy can be effectively absorbed by Ni3Al in fracture process,which effectively prevents the expansion of the crack line and make crack deflection.So it greatly enhance the toughness of the composites.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2009年第S2期448-452,共5页
Journal of Materials Engineering
关键词
熔渗
复合材料
微观组织
断裂韧性
melt infiltration
composites
microstructure
fracture toughness
