7050铝合金表面喷丸强化层内纳米结构微观组织结构分析

摘要

A nanostructured surface layer was fabricated on 7050 aluminum alloy by using shot peening technique. The structure and properties of the nanostructure surface layer were characterized by means of Electron back⁃scattering diffraction ( EBSD) , transmission electron microscope ( TEM) and X⁃ray diffraction. The results show that a nanostructured surface layer with the depth of about 150μm is formed after shot peening. The layer is composed of nanometer structures varying in orientation coming from the original grain refinement. The residual stress on surface turns into tensile and the hardness decreases significantly. Compare to the bulk material, the surface hardness decreases by about 70%.%利用喷丸技术在7050铝合金表面制备了纳米结构表面层。采用EBSD、TEM和XRD等方法分析了表面纳米结构层的组织结构。试验结果表明，采用喷丸技术可以在7050铝合金表面制备出纳米结构表面层，表面层是由原始晶粒细化成由表及里梯度分布的不同取向纳米级结构构成，深度～150μm。7050铝合金表面纳米化使材料的表层残余应力变成拉应力，硬度明显降低，与基体相比，表层的硬度降低了～70％。