7050铝合金表面纳米晶层的热稳定性研究  

Thermal stability of 7050 aluminum alloy nanocrystalline surface layer

作　　者：麦永津[1] 揭晓华[1] 刘莉莉[1] 于能 郑向新 

机构地区：[1]广东工业大学材料与能源学院,广东广州510006 [2]广东巨轮模具股份有限公司,广东揭阳515500

出　　处：《金属热处理》2009年第10期5-8,共4页Heat Treatment of Metals

基　　金：广东省教育部产学研结合项目(2008B090500084);粤港关键领域重点突破项目(TC09B863-2)

摘　　要：在普通喷丸设备上增加增压罐,采用增压喷丸方法在7050铝合金表面制备出平均直径约为30 nm的纳米晶层。通过差示扫描量热法研究了纳米晶层的热流量随温度的变化,利用K issinger方程计算得到7050铝合金经表面纳米化后其晶粒长大激活能比未处理样品高26.6 kJ/mo。lX射线衍射分析结果表明随着退火温度的升高,B ragg峰宽化明显减少,Scherrer-W ilson公式估算得到的晶粒尺寸在180-220℃明显增大。同时,显微硬度测试结果表明在此温度区间硬度相应迅速下降。因此,认为7050铝合金表面纳米晶层的热稳定温度在200℃以下。With the help of a new technique called accelerated-pressure shot peening which is the combination of common shot peening equipment with a pressurizing vessel, a nanocrystalline layer with ultrafine grains （ average diameter 30 nm） was fabricated on the surface of 7050 aluminum alloy. Heat flow of the nanocrystalline layer varied with temperature was investigated by differential scanning calorimetry （DSC） and the activation energy of the as-treated sample increased 26. 6 kJ/mol more than the as-reserved sample, which was calculated by Kisssinger equation. X-ray diffraction results show that the broadening of Bragg peaks decreases with the increasing of the annealing temperature, and grain size calculated by Scherrer-Wilson equation obviously increases from 180 to 220 ℃, and the microhardness clearly decreases at such temperature range. Therefore, it can be considered that the temperature range of thermal stability for aluminum alloy nanocrystalline layer is under 200 ℃.

关 键 词：7050铝合金 增压喷丸 表面纳米化 热稳定性 

分 类 号：TG142.31[一般工业技术—材料科学与工程]