Deformation twinning in Ni–Mn–Ga micropillars with 10M martensite
AUTOR(ES)
Reinhold, M.
FONTE
American Institute of Physics
RESUMO
The maximum actuation frequency of magnetic shape-memory alloys (MSMAs) significantly increases with decreasing size of the transducer making MSMAs interesting candidates for small scale actuator applications. To study the mechanical properties of Ni–Mn–Ga single crystals on small length scales, two single-domain micropillars with dimensions of 10×15×30 μm3 were fabricated from a Ni–Mn–Ga monocrystal using dual beam focused ion beam machining. The pillars were oriented such that the crystallographic c direction was perpendicular to the loading direction. The pillars were compressed to maximum stresses of 350 and 50 MPa, respectively. Atomic force microscopy and magnetic force microscopy were performed prior to fabrication of the pillars and following the deformation experiments. Both micropillars were deformed by twinning as evidenced by the stress-strain curve. For one pillar, a permanent deformation of 3.6% was observed and ac twins (10M martensite) were identified after unloading. For the other pillar, only 0.7% remained upon unloading. No twins were found in this pillar after unloading. The recovery of deformation is discussed in the light of pseudoelastic twinning and twin-substrate interaction. The twinning stress was higher than in similar macroscopic material. However, further studies are needed to substantiate a size effect.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2766397Documentos Relacionados
- Effect of cooling rate on (ε, α') martensite formation in twinning/transformation-induced plasticity Fe-17Mn-0.06C steel
- Superelasticity in Polycrystalline Ni-Mn-Ga-Fe Microwires Fabricated by Melt-extraction
- O efeito magnetocalórico nas ligas Heusler Ni54[Mn(1-x)Fex]19Ga27
- Rapidly Quenched Ni45Fe5Mn40Sn10 Heusler Alloys
- Martensite Transformation Intergrain and Intragrain Autocatalysis in Fe-Ni alloys