X-ray diffraction of nitinol orthodontic arch wires

PRODUÇÃO DE LIGAS DE MEMÓRIA DE FORMA DE Ni-Ti-Al COM ELEMENTO LIGANTE DE NIÓBIO - RESULTADOS PARCIAIS

“…A amostra com a composição de nitinol puro (CDP1) apresentou os picos de difração bem definidos em (110) para austenita com 2Θ de 42,5°, em (211) para austenita com 2Θ de 79,0°e em (202) para martensita com 2Θ de 65,0° (Iijima et al, 2003;Thayer et al, 1995). Este difratograma serviu como referência para a análise dos difratogramas apresentados para as demais amostras produzidas.…”

“…No CDP3, além dos picos presentes no CDP1 e no CDP2, também, observou-se a presença de um novo pico (220) para a austenita mais acentuado, o que pode ser relacionado ao aumento de nióbio na amostra e seu efeito estabilizador da fase β (Iijima et al, 2003;Thayer et al, 1995).…”

Orthodontic material applications over the past century: Evolution of research methods to address clinical queries

“…26 ii) Furthermore, experimental instrumentation included advanced analytical tools such as X-ray diffraction 27 and Differential scanning calorimetry, 28 which although did not provide a direct result on the actual mechanical profile of the archwires, assisted essentially in explaining the performance of materials in mechanical tests and improved our understanding of the mechanisms underlying the load-deformation curve of these wires.…”

Transformation behavior of nickel-titanium orthodontic wires under tensile load

“…The R-phase, named for its rhombohedral structure, typically forms during the forward and reverse transformations between martensite and austenite 14,15) . The transformation behavior of nickel-titanium wires have previously been studied by differential scanning calorimetry (DSC) 8,16) , temperature-modulated differential scanning calorimetry (TMDSC) 17) , transmission electron microscopy (TEM) 18) , X-ray diffraction (XRD) 19,20) and micro X-ray diffraction (micro-XRD) 21) . Thermomechanical analysis (TMA), which measures the linear displacement of a material as a function of temperature, can provide information about the softening point, heat distortion, coefficient of linear expansion, and transformation temperatures.…”