Microstructure and mechanical behavior of directionally solidified Fe 35Ni 15Mn 25Al 25

X. Wu; I. Baker; M. K. Miller; K. L. More; H. Bei; H. Wu

doi:10.1016/j.intermet.2012.07.032

Microstructure and mechanical behavior of directionally solidified Fe ₃₅Ni ₁₅Mn ₂₅Al ₂₅

X. Wu, I. Baker, M. K. Miller, K. L. More, H. Bei, H. Wu

Center for Nanophase Matls Sciences

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

The effects of directional solidification (DS) processing on the microstructure and hardness of Fe ₃₅Ni ₁₅Mn ₂₅Al ₂₅ are examined. The microstructure consists of (Fe, Mn)-enriched B2-ordered (ordered b.c.c.) and (Ni, Al)-enriched L2 ₁-ordered (Heusler) phases aligned along <100> directions in a complex percolating morphology. Because of the slow cooling rate during DS processing, the phase size in the DS alloy was approximately 3 times greater than that of an arc-melted alloy. Precipitates were found within both phases of the as-DS alloy, but not in the as-arc-melted alloy. Upon annealing, the phase size increased but with no significant change in the composition of the phases, while the interphase interfaces appeared to become sharper. The hardness of the DS alloy increased monotonically upon annealing, and showed an inverse relationship with the phase size before the formation of large β-Mn-structured precipitates. Several theoretical models are considered that might explain this variation of hardness with phase width. Longer annealing resulted in growth of the β-Mn-structured precipitates, causing a further 50% hardness increase.

Original language	English
Pages (from-to)	413-422
Number of pages	10
Journal	Intermetallics
Volume	32
DOIs	https://doi.org/10.1016/j.intermet.2012.07.032
State	Published - Jan 2013

Funding

This research was supported by the US Department of Energy, Office of Basic Energy Sciences (DOE grant DE-FG02-07ER46392). Research at the ORNL ShaRE User Facility was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy (Dr. M. K. Miller and Dr. K. L. More). Dr. H. Bei was supported by the U.S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division. The authors gratefully acknowledge Dr. Easo George of Oak Ridge National Lab for provision of the large ingots for DS, and K. F. Russell for technical assistance.

Funders	Funder number
Scientific User Facilities Division
U.S. Department of Energy	DE-FG02-07ER46392
Basic Energy Sciences
Oak Ridge National Laboratory
Division of Materials Sciences and Engineering

Keywords

A. Nanostructured intermetallics
B. Mechanical properties at ambient temperature
F. Atom microprobe
F. Electron microscopy, transmission

Access to Document

10.1016/j.intermet.2012.07.032

Cite this

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title = "Microstructure and mechanical behavior of directionally solidified Fe 35Ni 15Mn 25Al 25 ",

abstract = "The effects of directional solidification (DS) processing on the microstructure and hardness of Fe 35Ni 15Mn 25Al 25 are examined. The microstructure consists of (Fe, Mn)-enriched B2-ordered (ordered b.c.c.) and (Ni, Al)-enriched L2 1-ordered (Heusler) phases aligned along <100> directions in a complex percolating morphology. Because of the slow cooling rate during DS processing, the phase size in the DS alloy was approximately 3 times greater than that of an arc-melted alloy. Precipitates were found within both phases of the as-DS alloy, but not in the as-arc-melted alloy. Upon annealing, the phase size increased but with no significant change in the composition of the phases, while the interphase interfaces appeared to become sharper. The hardness of the DS alloy increased monotonically upon annealing, and showed an inverse relationship with the phase size before the formation of large β-Mn-structured precipitates. Several theoretical models are considered that might explain this variation of hardness with phase width. Longer annealing resulted in growth of the β-Mn-structured precipitates, causing a further 50% hardness increase.",

keywords = "A. Nanostructured intermetallics, B. Mechanical properties at ambient temperature, F. Atom microprobe, F. Electron microscopy, transmission",

author = "X. Wu and I. Baker and Miller, {M. K.} and More, {K. L.} and H. Bei and H. Wu",

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AU - Baker, I.

AU - Miller, M. K.

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AU - Bei, H.

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N2 - The effects of directional solidification (DS) processing on the microstructure and hardness of Fe 35Ni 15Mn 25Al 25 are examined. The microstructure consists of (Fe, Mn)-enriched B2-ordered (ordered b.c.c.) and (Ni, Al)-enriched L2 1-ordered (Heusler) phases aligned along <100> directions in a complex percolating morphology. Because of the slow cooling rate during DS processing, the phase size in the DS alloy was approximately 3 times greater than that of an arc-melted alloy. Precipitates were found within both phases of the as-DS alloy, but not in the as-arc-melted alloy. Upon annealing, the phase size increased but with no significant change in the composition of the phases, while the interphase interfaces appeared to become sharper. The hardness of the DS alloy increased monotonically upon annealing, and showed an inverse relationship with the phase size before the formation of large β-Mn-structured precipitates. Several theoretical models are considered that might explain this variation of hardness with phase width. Longer annealing resulted in growth of the β-Mn-structured precipitates, causing a further 50% hardness increase.

AB - The effects of directional solidification (DS) processing on the microstructure and hardness of Fe 35Ni 15Mn 25Al 25 are examined. The microstructure consists of (Fe, Mn)-enriched B2-ordered (ordered b.c.c.) and (Ni, Al)-enriched L2 1-ordered (Heusler) phases aligned along <100> directions in a complex percolating morphology. Because of the slow cooling rate during DS processing, the phase size in the DS alloy was approximately 3 times greater than that of an arc-melted alloy. Precipitates were found within both phases of the as-DS alloy, but not in the as-arc-melted alloy. Upon annealing, the phase size increased but with no significant change in the composition of the phases, while the interphase interfaces appeared to become sharper. The hardness of the DS alloy increased monotonically upon annealing, and showed an inverse relationship with the phase size before the formation of large β-Mn-structured precipitates. Several theoretical models are considered that might explain this variation of hardness with phase width. Longer annealing resulted in growth of the β-Mn-structured precipitates, causing a further 50% hardness increase.

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