摘要
铌钛铬铝合金因为具有密度低、高温强度高、抗氧化能力强等优点,有望成为下一代的高温结构材料,将被广泛应用于航天、航空等领域。用非自耗真空电弧炉熔炼了几种典型成分的铌钛铬铝合金铸锭,运用金相、XRD、SEM和EDS等多种分析方法,研究了其微观组织结构。结果表明:电弧熔炼的Nb-40Ti-15Al合金铸锭中,呈现出典型的底部激冷晶、柱状晶和等轴晶的凝固组织;在Nb-40Ti-10Cr合金中,铬富集在晶界和亚晶界,使合金有发生沿晶脆断的可能性;对于Nb-40Ti-20Cr合金,随着合金中铬元素的增加,凝固过程显著发生改变。由于合金中溶质铬的增加,产生成分过冷,使得其微观组织从平直晶界向粗大的树枝晶演变;而在Nb-40Ti-10Al-10Cr合金中,铝和铬的同时添加使亚晶界和析出相大量增殖。
Due to the advantages of low density,higher elevated temperature strength and good oxidation resistance,the Nb-Ti-Cr-Al alloy was estimated to become a new kind of high temperature materials.Therefore,it will be widely used in aerospace,aviation and other fields.In this paper,a few Nb-Ti-Cr-Al alloys with different composition were prepared by arc melting method,and analyzed by metallographic method,XRD,SEM and EDS.The results indicated,in Nb-40Ti-15Al alloy ingot,the solidified structure was typical little equiaxed grains,columnar crystals and equiaxed crystals.And in the Nb-40Ti-10Cr alloy,Cr element enriches in the grain boundaries and subgrain sector;it is possible to induce intergranular fracture along the grain.As the content of Cr element increased in Nb-Ti-Cr alloy,constitutional supercooling occurred in solidification process,and the microstruture changed from straight crystal boundaries to dendrite in Nb-40Ti-20Cr alloy.As for Nb-40Ti-10Cr-10Al alloy,the addition of Al and Cr will lead to a great number of subboundary and precipitated phase proliferation.
出处
《湖南有色金属》
CAS
2012年第2期47-50,74,共5页
Hunan Nonferrous Metals
基金
宁夏自然科学基金(NZ1102)
宁厦大学自然科学基金(ZR1107)
