Analysis of Microstructure and Strengthening Mechanisms in Laser Surface Alloyed Fe-Cr and Fe-C-Cr Alloy Systems.
Abstract
The effects of rapid melting and subsequent quenching on the solidification behavior and solid state transformation structures of laser surface alloyed Fe-Cr, Fe-Ni, Fe-Cr-Ni and Fe-C-Cr systems were investigated as functions of composition (0-50%Cr, 0-20%Ni, 0-20%Cr/Ni, 0-1C%) and cooling rate. The microstructures were characterized by optical, scanning and thin foil transmission electron microscopy. The effects of laser parameters (laser power, beam size and scan rate) and coating variables (composition, thickness and morphology) on the penetration depth and melt width were also evaluated. The microstructures of Fe-Cr alloys were ferritic in nature, irrespective of the composition (0-50%Cr) and cooling rate. The transformation structures of Fe-5%Ni and Fe-6%Cr-2%Ni alloys exhibited a mixture of martensite and ferrite. The transformation structures of Fe-C-Cr alloys were studied as functions of the carbon (0.2-1.0%C) and chromium contents (0-40%Cr). The rapid solidification effects including the retention of supersaturated austenite, lack of carbide precipitation and the morphology of phases are discussed as functions of alloy content and cooling rate.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 22, 1983
- Accession Number
- ADA137971
Entities
People
- W. E. Wood