Generating duplex microstructures by nitriding; nitriding of iron based Fe–Mn alloy

Abstract

Nitriding of Fe–2 at-%Mn alloy at 650°C employing a nitriding potential of 0·05 atm− 1/2 resulted in a highly complex microstructural development as a function of depth below the specimen surface: a surface adjacent layer exhibiting an austenite–martensite duplex microstructure, followed by an intermediate region showing a ferrite–austenite duplex microstructure, and at even larger depths a region where an austenite layer covers the grain boundaries of the ferrite matrix grains. Development of this complex microstructure is attributed to the strong austenite stabilising effects of Mn and N. This work demonstrates the power of a relatively simple nitriding treatment to realise a highly complex microstructure known to be associated with strongly enhanced mechanical properties.

3D Forging Simulation of a Multi-Partitioned Titanium Alloy Billet for a Medical Implant

“…The type of billet partitioning, such as the core and outer shell structure of Model 2, is readily feasible with a short heat treatment-whereby the atmospheric heat only has time to conduct to a certain depth from the surface to give a microstructural variation in the partitions, or with a mass transfer operation such as carburising, nitriding or carbonitriding, to give a compositional variation in partitions. These techniques would, therefore, determine a succession of compositions from the surface to the unaffected core region [31], which may be represented with a series of discrete partition layers. Whilst these surface heat treatment and mass transfer techniques could equally be adopted post forging to generate surface modifications, they would not allow for any internal partitioning.…”

Alloying Element Nitride Development in Ferritic Fe-Based Materials Upon Nitriding: A Review

“…It allows to arrange the reactivities of various Me with N in binary ferritic alloys in roughly this order: Ti > V > Al > Cr > Si > Mo. Note that in binary Fe-Mn alloys, complex phase transformation reactions take place (Ref [38][39][40][41][42], which has led to its exclusion from this series.…”

Experimental Investigation of Al-CuMgMn Alloy Developed by Laser Beam Surface Modification for Wear Resistance

“…In the other method, a binder is employed to pre-place the alloying material, and it is also possible to deliver the wire form of the alloying materials into the melt pool [27]. Laser surface alloying involves simultaneously melting and mixing of the alloying material containing the alloyed additions with the treated material (base material) [28]. Changing the chemical composition of the aluminum alloy causes changes in the properties of the material.…”