|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Thermal and Mechanical Stability of Nanocrystalline Materials
||Sensitization in Grain Size Gradients – Investigating the Effects of Low Temperature, Long Term Annealing on the Corrosion and Mechanical Response of Nanocrystalline Aluminum Alloys
||Heather Murdoch, Denise Yin, B. Chad Hornbuckle, Joseph Labukas
|On-Site Speaker (Planned)
A particular thermal stability challenge in aluminum alloys such as AA5083 is sensitization, wherein precipitation of β phase at grain boundaries during long term exposure to low temperatures sets up galvanic couples that lead to pronounced intergranular corrosion. In this work we use surface mechanical attrition treatment (SMAT), a severe surface plastic deformation process, to induce a grain size gradient in a bulk 5083 substrate. This process has the benefit of concentrating nanocrystalline/ultrafine grains at the surface where they have the most potential for improving corrosion and wear resistance, while leaving coarse grains intact within the sample for bulk ductility. This study evaluates the origin and effect of precipitation on intergranular corrosion through altering the population of grain boundary types (β phase precipitation) and significantly reducing grain size (β phase GB coverage). The stability of the grain size gradient under mechanical loading is also evaluated before and after sensitization.
||Planned: Supplemental Proceedings volume