( 1. 太原理工大學(xué) 材料科學(xué)與工程學(xué)院，太原 030024;
2. 中國(guó)科學(xué)院 金屬研究所，沈陽(yáng) 110016)
摘 要: 采用高能噴丸技術(shù)在1420鋁合金上制備出納米晶結(jié)構(gòu)表層，利用X射線衍射儀、透射電子顯微鏡及高分辨電子顯微鏡研究由表層沿厚度方向的結(jié)構(gòu)變化特征，并對(duì)硬度沿厚度方向的變化進(jìn)行分析。結(jié)果表明：經(jīng)過(guò)表面高能噴丸處理，樣品表面形成了厚度約為20 μm的納米晶層，平均晶粒尺寸由約20 nm逐漸增加到約100 nm；距表層約20~50 μm為亞微細(xì)晶層；表面納米化的程度與塑性變形量有關(guān)；表面納米化是通過(guò)位錯(cuò)滑移的塑性變形方式實(shí)現(xiàn)的；與樣品的內(nèi)部相比，表面硬度顯著提高。
關(guān)鍵字: 鋁合金；高能噴丸；表面納米化；顯微結(jié)構(gòu)；硬度
surface nanocrystallization of aluminum alloy
WEI Ying-hui1，XU Bin-she1
（ 1. College of Materials Science and Engineering,
Taiyuan University of Technology, Taiyuan 030024, China;
2. Institute of Metal Research, The Chinese Academy of Sciences,
Shenyang 110016, China）
Abstract: A nanostructured surface layer was fabricated on an aluminum alloy 1420 by using a high-energy shot peening (HESP) technique. HESP induced structure alone the depth of the treated sample surface layer was characterized by means of X-ray diffraction,transmission electron microscope and high-resolution electron microscope; and the hardness variation along the depth of the treated sample was examined. Experimental results show that nanostructured surface layer of about 20 μm of thickness is formed after HESP, the average grain size increases from about 20 nm in the surface layer to about 100 nm at a depth of 20 μm. In the region of 20-50μm deep from the surface, there exists submicro-fine grained layer. The degree of the surface crystallization is related to the amount of the plasticity deformation.The surface nanocrystallization can realize by the method of the plastic deformation of dislocation slipping. The hardness of nanostructured surface layer is enhanced significantly after HESP compared with that of the initial sample.
Key words: aluminum alloy; high-energy shot peening; surface nanocrystallization; microstructure; hardness
