Ti对Nb-20Si-5Al超高温合金性能的影响  

Effects of Ti Addition on the Properties of Nb-20Si-5Al Ultrahigh Temperature Alloy

作　　者：龙文元[1] 陈勤 Long Wenyuan;Chen Qin(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University)

机构地区：[1]南昌航空大学航空制造工程学院,南昌330063

出　　处：《特种铸造及有色合金》2021年第3期279-283,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51271091);江西省自然科学基金资助项目(20161BAB206107)。

摘　　要：采用放电等离子烧结法(SPS)制备了Nb-20Si-5Al-xTi(x=0,18,20,22,摩尔分数)超高温合金,研究了Ti加入量对Nb-20Si-5Al合金的室温断裂韧度和高温抗氧化性的影响。结果表明,随着Ti加入量的增加,超高温合金的相组成由Nbss、Nb_(5)Si_(3)和Al3Nb相转变成为Nbss、(Nb,Ti)5Si3和Ti相。Ti能明显改善Nb-20Si-5Al超高温合金的断裂韧度和高温抗氧化性能,随着Ti加入量的增加均先提高然后降低,在Ti加入量为20%时,合金断裂韧度最大,为7.41 MPa·m^(1/2),相比未加Ti时提高了约56.9%,其高温氧化速率最低,为0.72×10^(-4)g^(2)/(cm^(4)·h)。添加Ti元素后,其氧化产物中出现Ti_(2)Nb_(10)O_(29)、TiNb_(2)O_(7)、TiO_(2)等,可以提高其氧化膜的致密性,从而提高高温抗氧化性能。Nb-20Si-5Al-xTi(x=0,18,20,22,%)ultrahigh temperature alloys were prepared by the spark plasma sintering(SPS)technology.The effects of Ti addition on the fracture toughness and high temperature oxidation resistance of the alloys were analyzed.The results reveal that the phase composition of Nb-20Si-5Al ultrahigh temperature alloys is transformed from Nbss、(Nb,Ti)5Si3and Al3Nb to Nbss、(Nb,Ti)5Si3、Ti and Al3Ti phases.The fracture toughness and high temperature oxidation resistance of alloys can be obviously improved with the addition of Ti element,which are both increased firstly and then decreased with the increase of Ti content.When the content of Ti is 20%,the fracture toughness reaches the maximum value of 7.41MPa·m1/2,which is 56.9%higher than that of one without Ti,and the high temperature oxidation rate is the lowest,which is 0.72×10^(-4)g^(2)/(cm^(4)·h).After adding Ti,Ti_(2)Nb_(10)O_(29)、TiNb_(2)O_(7)、TiO_(2)and so on can be observed in the oxidation products,which improve the compactness of the oxide film,thus enhancing the oxidation resistance at high temperature.

关 键 词：放电等离子烧结 Nb-Si超高温合金 高温抗氧化性 断裂韧性 

分 类 号：TG146[一般工业技术—材料科学与工程]