喷射沉积AlFeVSi合金热暴露过程中相转变与沉积态组织特点  

Phase transformation during thermal exposure and microstructural characteristics of spray deposited billets of AlFeVSi aluminum alloy

作　　者：肖于德[1] 钟掘 黎文献[1] 马正青[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学机电工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2007年第5期795-801,共7页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展规划项目(G1999064900);中国博士后科学基金资助项目(2005038560)

摘　　要：采用喷射沉积工艺制备快速凝固AlFeVSi合金薄片和沉积管坯,通过示差热分析、X射线衍射分析、金相显微组织观察、透射电镜组织观察、硬度测试等检测手段,研究了喷射沉积AlFeVSi合金快凝薄片在高温热暴露过程中的相变和组织演变规律,并分析了喷射沉积AlFeVSi合金坯组织特点。结果表明,喷射沉积AlFeVSi快凝薄片基本上为呈微胞状的过饱和α-Al固溶体。加热温度低于500℃时,在高温热暴露过程中微胞状结构发生分解,α-Al过饱和固溶体脱溶,形成α-Al+Al12(Fe,V)3Si(bcc,a≈1.260 nm)弥散颗粒的分解产物,当温度高于500℃时,Al12(Fe,V)3Si颗粒粗化聚集,并以独立形核长大的方式生成θ-Al13Fe4块状相。随着热暴露温度升高,喷射沉积AlFeVSi合金薄片的硬度呈下降趋势。喷射沉积AlFeVSi坯主要由α-Al固溶体和Al12(Fe,V)3Si颗粒组成,但也存在少量含粗大片状或块状相的非快速凝固组织。The rapidly solidified flake and pipe blank of spray deposited AIFeVSi aluminum alloy were prepared through the multi-layer spray deposition process in the atomization medium of nitrogen gas. Phase transformation and mierostruetural evolution of the as-deposited flakes during thermal exposure at high temperature were studied by means of differential thermal analysis （DTA）, X-ray diffraction （XRD）, optical microscopy （OM）, transmission electron microscopy （TEM） and hardness measurement, and mierostruetures of the spray deposited billet of the Al-8.5Fe-1.3V-1.7Si aluminum alloy were characterized. The results show that the rapidly solidified flakes of AlFeVSi alloy mainly consist of α-Al supersaturated solid solution with mieroeellular structure. During thermal exposure below 500 ℃, the mieroeellular structure decomposes, and the α-Al supersaturated solid solution transforms into the mixture of Al12（Fe,V）3 Si particles dispersed in α-Al matrix, while above 500℃ the Al12（Fe,V）3Si particles coarsen and congregate, and even form lumpish θ-Al13Fe4 phase in an independently nucleating and growing mode. With the increase of exposure temperature, hardness of the rapidly solidified flake of spray deposited AIFeVSi aluminum alloy exhibits obvious reducing trend. The spray deposited billet of the Al-8.5Fe-1.3V- 1.7Si aluminum alloy consists on the whole of two phase mixture of α-Al and Al12（Fe,V）3Si （bee, α≈1.260 nm）, which is characterized generally as the fine Al12（Fe, V）3Si particles dispersed uniformly in the α-Al matrix, but there appears a very small amount of non-rapidly solidified mierostruetures with coarse lumpish particles of θ-Al13Fe4 phase in the condition of near rapid solidification or slowly solidification.

关 键 词：喷射沉积 快速凝固 铝合金 相变 

分 类 号：TG146.2[一般工业技术—材料科学与工程]