中文摘要：

采用超声表面加工处理方法在45钢上制备出纳米结构表层．TEM（透射电子显微镜）、XRD（X射线衍射）、粗糙度和显微硬度试验结果表明：经超声处理后，样品表层的晶粒可细化至纳米量级，平均晶粒尺寸为50nm，且在某些区域出现纳米晶与非晶嵌套结构，表面形成残余压应力，表面粗糙度值降为原始样品的1／100，与样品心部相比，表层硬度显著提高．

英文摘要：

A nanostructured surface layer was fabricated on 45 steel by using ultrasonic surface processing. Resuits of TEM（ transmission electron microscope）, XRD（ X-ray diffractometer）, surface roughness and microhardness tests indicated that the process induced nanocrystallization and partial amorphization, the average grain size is 50 nm, residual compression stress forms on the surface, the roughness of the processed specimen is highly decreased and the hardness is improved compared with the center of the specimen.