Influence of quenching rates on equiatomic NiTi ribbons fabricated by melt-spinning

Abstract

Quenching rates, in terms of circumferential wheel speed in melt-spinning, play an important role in the resultant characteristics of the ribbons. In this study, the influence of various wheel speeds on ribbon dimensions, cross-sectional microstructures, and crystallographic phases within samples were investigated. The Ni-50.3at.%Ti melt-spun ribbons were produced under 200 mbar He atmosphere at wheel speeds of 5-30 ms-1 using a quartz crucible coated internally with Y2O3. The different wheel speeds led to different sample dimensions and cooling rates. The microstructures of the samples were observed using optical microscopy and TEM, while the shape memory effect of samples and the existing phases were studied by differential scanning calorimetry, x-ray diffraction, and tensile tests. © 2009 ASM International.