In:
Metallurgical and Materials Transactions A, Springer Science and Business Media LLC, Vol. 46, No. 3 ( 2015-03), p. 1154-1167
Abstract:
Ni-free austenitic steels alloyed with Cr and Mn are an alternative to conventional Ni-containing steels. Nitrogen alloying of these steel grades is beneficial for several reasons such as increased strength and corrosion resistance. Low solubility in liquid and δ -ferrite restricts the maximal N-content that can be achieved via conventional metallurgy. Higher contents can be alloyed by powder-metallurgical (PM) production via gas–solid interaction. The performance of sintered parts is determined by appropriate sintering parameters. Three major PM-processing routes, hot isostatic pressing, supersolidus liquid phase sintering (SLPS), and solid-state sintering, were performed to study the influence of PM-processing route and N-content on densification, fracture, and mechanical properties. Sintering routes are designed with the assistance of thermodynamic calculations, differential thermal analysis, and residual gas analysis. Fracture surfaces were studied by X-ray photoelectron spectroscopy, secondary electron microscopy, and energy dispersive X-ray spectroscopy. Tensile tests and X-ray diffraction were performed to study mechanical properties and austenite stability. This study demonstrates that SLPS process reaches high densification of the high-Mn-containing powder material while the desired N-contents were successfully alloyed via gas–solid interaction. Produced specimens show tensile strengths 〉 1000 MPa combined with strain to fracture of 60 pct and thus overcome the other tested production routes as well as conventional stainless austenitic or martensitic grades.
Type of Medium:
Online Resource
ISSN:
1073-5623
,
1543-1940
DOI:
10.1007/s11661-014-2701-7
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2015
detail.hit.zdb_id:
1179415-X
detail.hit.zdb_id:
2037517-7
detail.hit.zdb_id:
192156-3
SSG:
19,1
