INVESTIGADORES
MALARRIA Jorge Alberto
artículos
Título:
Heat Treatments of Fe-Mn-Si Based Alloys: Mechanical Properties and Related Shape Memory Phenomena
Autor/es:
A. DRUKER; A. PEROTTI; A. BARUJ; J. MALARRÍA
Revista:
Journal of ASTM International
Editorial:
ASTM International
Referencias:
Lugar: West Conshohocken PA; Año: 2011 vol. 8 p. 1 - 9
ISSN:
1546-962X
Resumen:
Heat treatments are usual
means for modifying alloy microstructures and, consequently, to control
mechanical properties. The aim of this work was to find suitable processes for improving
the shape memory effect (SME) of Fe-Mn-Si-based alloys. In particular, we
studied mechanisms that affect the plastic deformation of the austenite phase.
A Fe-15Mn-5Si-9Cr-5Ni alloy was deformed by rolling at different temperatures
and subsequently annealed at recovery- and recrystallization-temperature. The mechanical
properties of the material after processing were evaluated by performing tension
and flexure tests. The SME of room-temperature deformed specimens was measured
after heating them to 550oC for shape recovery. We found that the
material rolled at 800ºC
followed by an annealing treatment at 650ºC recovers nearly 95% of a 3% deformation.
In this thermo-mechanical condition, the material has a yield stress of 450 MPa
and an ultimate tensile strength (UTS) of 880 MPa, corresponding to a total
elongation of about 16%. Optical and electron microscopy observations show that
the matrix annealed at high temperature contains a low density of defects. As a
consequence, there are fewer nucleation sites for martensite and the associated
SME is low. On the other hand, annealing at intermediate temperatures (around
650oC) produces a favorable structure containing a large density of
stacking faults