CUED Publications database

The microstructure and mechanical properties of ball-milled stainless steel powder: The effect of hot-pressing vs. laser sintering

Nachum, S and Fleck, NA (2011) The microstructure and mechanical properties of ball-milled stainless steel powder: The effect of hot-pressing vs. laser sintering. Acta Materialia, 59. pp. 7300-7310. ISSN 1359-6454

Full text not available from this repository.

Abstract

The microstructure and mechanical properties of sintered stainless steel powder, of composition AISI 420, have been measured. Ball-milled powder comprising nanoscale grains was sintered to bulk specimens by two alternative routes: hot-pressing and microlaser sintering. The laser-sintered alloy has a porosity of 6% and comprises a mixture of delta ferrite and tempered martensite, and the relative volume fraction varies along the axis of the specimen due to a thermal cycle that evolves with progressive deposition. In contrast, the hot-pressed alloy has a porosity of 0.7% and exhibits a martensitic lath structure with carbide particles at the boundaries of the prior austenite grains. These differences in microstructure lead to significant differences in mechanical properties. For example, the uniaxial tensile strength of the hot-pressed material is one-half of its compressive strength, due to void initiation at the carbide particles at the prior austenite grain boundaries. Nanoindentation measurements reveal a size effect in hardness and also reveal the sensitivity of hardness to the presence of mechanical polishing and electropolishing. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type: Article
Uncontrolled Keywords: AISI 420 stainless steel Ball-milling Martensite Microlaser sintering Nanoindentation
Subjects: UNSPECIFIED
Divisions: Div C > Materials Engineering
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 11:22
Last Modified: 08 Dec 2014 02:35
DOI: 10.1016/j.actamat.2011.08.004