High-strength shape memory steels alloyed with nitrogen

Journal Article · Thu Aug 15 04:00:00 EDT 1996 · Scripta Materialia

DOI:https://doi.org/10.1016/1359-6462(96)00171-6· OSTI ID:271625

Ullakko, K ^[1]; Jakovenko, P T; Gavriljuk, V G ^[2]

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1. Massachusetts Inst. of Tech., Cambridge, MA (United States)
2. Inst. for Metal Physics, Kiev (Ukraine)

Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels.

• OSTI ID: 271625
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 4 Vol. 35; ISSN 1359-6462; ISSN XZ503X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CHEMICAL COMPOSITION
CHROMIUM ALLOYS
DRAWING
ELONGATION
HOT WORKING
IRON BASE ALLOYS
MANGANESE ALLOYS
MECHANICAL PROPERTIES
MELTING
METALLURGICAL EFFECTS
NICKEL ALLOYS
NITROGEN
QUENCHING
ROLLING
SAMPLE PREPARATION
SHAPE MEMORY EFFECT
SILICON ALLOYS
STACKING FAULTS
TENSILE PROPERTIES
VANADIUM ALLOYS
YIELD STRENGTH