STP1532

    Heat Treatments of Fe-Mn-Si Based Alloys: Mechanical Properties and Related Shape Memory Phenomena

    Published: Apr 2012


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    Abstract

    Heat treatments are usual means for modifying alloy micro-structures 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 550°C for shape recovery. We found that the material rolled at 800°C followed by an annealing treatment at 650°C 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 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 tempera-tures (around 650°C) produces a favorable structure containing a large density of stacking faults.

    Keywords:

    shape memory, Fe–Mn–Si, rolling, microstructures


    Author Information:

    Druker, A.
    Facultad de Cs. Ex., Ingeniería y Agrimensura (UNR), Rosario,

    Perotti, A.
    Facultad de Cs. Ex., Ingeniería y Agrimensura (UNR), Rosario,

    Baruj, A.
    Centro Atómico Bariloche e Instituto Balseiro, San Carlos de Bariloche,

    Malarría, J.
    CONICET-Univ. Nacional de Rosario, Rosario,


    Paper ID: STP153220120020

    Committee/Subcommittee: D02.L0

    DOI: 10.1520/STP153220120020


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