Showing papers in "Materials Science and Engineering A-structural Materials Properties Microstructure and Processing in 1987"

The influence of laser surface treatment on the high temperature oxidation of Cr2O3-forming alloys☆

Abstract: The influence of laser glazing (melt-quenching) and laser surface alloying on the high-temperature oxidation of Incoloy 800H and stainless steel 316L at 1000°C in 1 atm dry oxygen has been investigated. The oxidation behaviour of the treated surfaces has been compared with that of untreated specimens using continuous weight-gain measurements and standard post-oxidation analysis techniques. Particular emphasis has been placed on the establishment of the Cr2O3 layer. Laser surface glazing promotes the development of the healing layer by providing additional rapid-diffusion paths for chromium to the surface. The relevant features of the process are retained alloy grain boundaries and alloy twins, laser-induced hyperfine microstructures and solidification artefacts. Laser alloying with chromium produces similar features but allows even more rapid establishment of the healing Cr2O3 layer; however, for stainless steel 316L, there was no evidence for suppression of breakdown of the scale which occurred for both untreated and laser-glazed surfaces. Some results of this on-going programme are presented and discussed.