Shape memory effect and related phenomena in a microalloyed Fe-Mn-Si alloy

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Materials Characterization; (United States)

OSTI ID:7108850

Li, J; Wayman, C M ^[1]

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1. Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering

An Fe-32Mn-6Si-0.05Nb-0.04C alloy aged at different temperatures was employed to study the [var epsilon] (hcp) martensite transformation, the mechanism of the shape memory effect (SME) associated with the [var epsilon] martensite transformation, the effect of precipitation strengthening, and the effect of thermomechanical treatment and deformation temperature on the SME. The results of transformation temperature studies show that the M[sub s] temperature for various heat-treated specimens is in the range of 75--100 C, the A[sub s] temperature is 112--125 C, and the Neel temperature of this material, T[sub N], is 8 C. The SME decreases with increasing plastic deformation and increases with decreasing deformation temperature and increasing thermomechanical training. The critical strength of aged specimens is higher than that of quenched ones due to the precipitation strengthening of NbC, which improves the SME for plastic deformation amounts less than 2% at room temperature. The microstructure observation by transmission electron microscopy shows that stacking faults play an important role in the formation of the [var epsilon] martensite. Surface relief examination at different temperatures and the electrical resistance versus temperature relationship reveal that the [epsilon] martensite transformation takes place continuously at temperatures below the T[sub N] temperature. An SME mechanism for Fe-Mn-Si based alloys is proposed.

• OSTI ID: 7108850
• Journal Information: Materials Characterization; (United States), Journal Name: Materials Characterization; (United States) Vol. 32:3; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360102* -- Metals & Alloys-- Structure & Phase Studies
AGING
ALLOYS
CARBON ADDITIONS
ELASTICITY
FABRICATION
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MATERIALS WORKING
MECHANICAL PROPERTIES
NIOBIUM ADDITIONS
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SILICON ALLOYS
TENSILE PROPERTIES
THERMODYNAMIC PROPERTIES
THERMOELASTICITY
THERMOMECHANICAL TREATMENTS