کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1608382 1516248 2015 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of chemical ordering annealing on martensitic transformation and superelasticity in polycrystalline Ni–Mn–Ga microwires
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
Effect of chemical ordering annealing on martensitic transformation and superelasticity in polycrystalline Ni–Mn–Ga microwires
چکیده انگلیسی


• Chemical ordering annealing on Ni–Mn–Ga microwires was found to reduce the defect density and internal stress.
• Chemical ordering annealing on Ni–Mn–Ga microwires was found to increase the MT temperatures, Curie point and saturation magnetization.
• Chemical ordering annealing on Ni–Mn–Ga microwires was found to decrease the SIM stress and improve the superelastic reversibility.
• Chemical ordering annealing on Ni–Mn–Ga microwires was found to weaken the temperature dependences of the superelastic stresses.

Polycrystalline Ni–Mn–Ga microwires of diameter 30–80 μm were prepared by melt-extraction technique on a large scale. The rapidly solidified microwires exhibit a fairly high ductility and excellent shape memory property. Here, with the aim to reduce the defect density, internal stress and compositional inhomogeneity in the as-extracted microwires, a stepwise chemical ordering annealing heat treatment was carried out and the effect of annealing on martensitic transformation, magnetic properties and superelastic behavior were investigated. The results indicate that annealing increase the transformation temperature and decrease the transformation hysteresis. These are related to composition homogenization, increase of atomic ordering and decrease in internal stress and defects. During mechanical tests, the stress-induced martensite (SIM) formation took place at a much lower stress after annealing treatment. The annealed microwires also demonstrate a lower superelastic hysteresis and a higher recovery rate compared to the as-extracted microwires. The temperature dependence of SIM stress is weaker after annealing, which is related to the enthalpy change (ΔH) and phase transformation temperature change according to the Clausius–Clapeyron relation.

Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 645, 5 October 2015, Pages 335–343
نویسندگان
, , , , ,