Karak, Swapan Kumar and Dutta Majumdar, J and Witczak, Zbigniew and Lojkowski, Witold and Ciupinski, Lukasz and Kurzydlowski, K J and Manna, Indranil (2013) Evaluation of microstructure and mechanical properties of nano-Y2O3-dispersed ferritic alloy synthesized by mechanical alloying and consolidated by high-pressure sintering. Metallurgical and Materials Transactions A-Physical Metallurg and Materials Science, 44A (6). pp. 2884-2894. ISSN 1073-5623

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Abstract

In this study, an attempt has been made to synthesize 1.0 wt pct nano-Y2O3-dispersed ferritic alloys with nominal compositions: 83.0 Fe-13.5 Cr-2.0 Al-0.5 Ti (alloy A), 79.0 Fe-17.5 Cr-2.0 Al-0.5 Ti (alloy B), 75.0 Fe-21.5 Cr-2.0 Al-0.5 Ti (alloy C), and 71.0 Fe-25.5 Cr-2.0 Al-0.5 Ti (alloy D) steels (all in wt pct) by solid-state mechanical alloying route and consolidation the milled powder by high-pressure sintering at 873 K, 1073 K, and 1273 K (600A degrees C, 800A degrees C, and 1000A degrees C) using 8 GPa uniaxial pressure for 3 minutes. Subsequently, an extensive effort has been undertaken to characterize the microstructural and phase evolution by X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive spectroscopy. Mechanical properties including hardness, compressive strength, Young's modulus, and fracture toughness were determined using micro/nano-indentation unit and universal testing machine. The present ferritic alloys record extraordinary levels of compressive strength (from 1150 to 2550 MPa), Young's modulus (from 200 to 240 GPa), indentation fracture toughness (from 3.6 to 15.4 MPaaem), and hardness (from13.5 to 18.5 GPa) and measure up to 1.5 through 2 times greater strength but with a lower density (similar to 7.4 Mg/m(3)) than other oxide dispersion-strengthened ferritic steels (< 1200 MPa) or tungsten-based alloys (< 2200 MPa). Besides superior mechanical strength, the novelty of these alloys lies in the unique microstructure comprising uniform distribution of either nanometric (similar to 10 nm) oxide (Y2Ti2O7/Y2TiO5 or un-reacted Y2O3) or intermetallic (Fe11TiY and Al9.22Cr2.78Y) particles' ferritic matrix useful for grain boundary pinning and creep resistance.

Item Type: Article
Subjects: Engineering Materials
Divisions: Director´┐Żs Secretariat
Depositing User: Bidhan Chaudhuri
Date Deposited: 12 Sep 2013 07:13
Last Modified: 12 Mar 2016 16:15
URI: http://cgcri.csircentral.net/id/eprint/2136

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