摘要
以Ti-42.5Al-8Nb-0.2W-0.2B-0.1Y(原子分数,%)合金为研究对象,通过热处理获得不同大小片层团的2种全片层显微组织,并在900℃空气条件下,进行了100 h的抗氧化性实验。利用OM、SEM、TEM、XRD和EDS对试样的微观结构、相组成及微区成分进行了分析。恒温氧化动力学结果表明:在900℃空气条件下,具有2种不同大小全片层组织的Ti Al合金,其恒温氧化动力学曲线符合近抛物线规律,且大片层组织合金的抗氧化性能优于小片层组织。氧化100 h后,大片层组织的合金其氧化增重为6.45 g/m^2,小片层组织的合金的氧化增重为7.62 g/cm^2。对合金截面进行观察后发现,具有大小片层团2种合金表面氧化物的厚度分别为5和7μm。通过对氧化动力学曲线、组织结构、氧化膜结构、氧化表面形貌进行综合分析,2种合金组织结构的不同影响了O元素在基体中的扩散,而扩散速率的不同最终导致2种Ti Al合金表现出不同的氧化行为。
The oxidation behavior of full-lamellar Ti-42.5Al-8Nb-0.2W-0.2B-0.1Y alloys with different colony sizes was investigated by a thermogravimetric method at 900℃ for 100 h in air.The microstructure and composition of the alloy as well as the oxide scales were analyzed by OM,SEM,EDS and XRD.It is found that the oxidation kinetic of the present Ti Al alloys accords with the parabolic law,and the alloy with larger lamellar colony has a better oxidation resistance than the one with smaller lamellar colony.The mass gain of the two samples with large and small lamellar colony after 100 h oxidation is 6.45 and 7.62 g/cm^2,respectively.And correspondingly the thickness of oxide scale is about 5 and 7 μm,respectively.Based on the analysis of oxidation kinetic and microstructure characterization,we conclude that the structural differences between the two samples which affect the diffusion rate of O element into the matrix result in different oxidation behavior.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2016年第7期1695-1699,共5页
Rare Metal Materials and Engineering
基金
National Key Basic Research Development Program of China("973"Program)(2011CB605503)
关键词
TIAL合金
全片层
片层团
氧化行为
TiAl alloys
full lamellar structure
lamellar colony
oxidation behavior
