|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Multiscale Architectured Materials (MAM II): Tailoring Mechanical Incompatibility for Superior Properties
||Gradient Nanostructure and Residual Stresses Induced by Ultrasonic Nano-crystal Surface Modification for Improved Mechanical Properties
||Chang Ye, Yalin Dong, Vijay K. Vasudevan
|On-Site Speaker (Planned)
Gradient nanostructured metallic materials attracted significant interests due to their unprecedented combination of strength, ductility and fatigue performance. Ultrasonic nanocrystal surface modification (UNSM) is a recently developed surface severe plastic deformation process that utilizes static load superimposed on dynamic ultrasonic impacts to induce plastic deformation on metal surfaces. Here we report how UNSM affects the microstructure and thus the properties and performance of 304 stainless steel and 52100 bearing steel. In 304 SS, nanograins have been observed in the top surface while highly dense deformation twins have been observed in the subsurface after UNSM. The sandwich microstructure with two strong surface layers and a compliant interior embedded with highly dense nanoscale deformation twins leads to both high strength and high ductility in SS 304. In 52100 bearing steel, the work-hardened surface layers and high magnitude of compressive residual stresses induced by UNSM lead to improved wear resistance and fatigue performance.