Transformation of mechanically alloyed Nb-Sn powder to Nb3Sn

Patankar, Swati; Froes, F. H.

doi:10.1007/s11661-004-0248-8

Cited by 4 publications

(2 citation statements)

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“…It is known that isomorphous b-stabilizer elements, such as Nb, exhibit slower diffusivities in Ti than the eutectoid elements of Fe, Co and Ni. 25 The structural analysis of the diffraction patters obtained using the Rietveld method showed that the lattice parameters for all the tested samples become reduced. In comparison to the ICDD data, it was found that high-energy milling and annealing have the smallest, but significant effect on the reduction of the size of a unit cell of the a and b phases.…”

Section: Resultsmentioning

confidence: 96%

Effect of ball milling on the properties of the porous Ti–26Nb alloy for biomedical applications

Dercz¹,

Matuła²

2017

Mater. Tehnol.

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The current study investigated the effect of the ball-milling time on the structural characteristics and pore morphology of a biomedical porous alloy. An open-cell porous material was synthesized by mechanical alloying and sintering. Commercially available elemental metal powders of Ti and Nb were used as the starting materials. Elemental metal powders with a nominal composition of Ti-26Nb (a/%) were milled in a planetary ball mill. During the testing, the powders were milled for two milling times: 50 h and 70 h. During the shorter milling time, the speed of 200 min -1 was applied, and during the longer milling time, the speed of 400 min -1 was applied. The powders were cold pressed under a pressure of 750 MPa and then sintered at 1000°C for 24 h. The effects of the powder milling time on the microstructure and mechanical properties of the porous structure were investigated with optic microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness, nanoindentation and nanomachining tests. The hardness and elastic modulus were calculated from the load-displacement data obtained with nanoindentation using a three-sided, pyramidal, diamond (Berkovich) indenter tip. The X-ray diffraction results confirmed the presence of the a and b phases. An analysis of diffraction patterns revealed a decrease in the lattice parameters for the 70 h milling. In summary, it should be pointed out that the material has a hierarchical structure, obtained during the successive stages of milling. The observed grains are composed of many smaller grains, the size of which decreased with an increase in the milling time. Keywords: mechanical alloying, porosity, nanoindentation, Ti-26Nb alloy V {tudiji so preiskovali vpliv razli~no dolgega~asa krogli~nega mletja na strukturne zna~ilnosti in morfologijo por biomedicinske porozne Ti-26Nb zlitine (a/%). Porozni material z odprtimi celicami je bil sintetiziran z mehanskim legiranjem in sintranjem. Osnovni metalur{ki prahovi z nominalno vsebnostjo Ti-26Nb (a/%) so bili mleti v planetarnem krogelnem mlinu. Med testiranjem so bili prahovi mleti pri dveh razli~nih~asih: 50 h in 70 h. Med kraj{im~asom mletja je bila uporabljena hitrost mletja 200 min -1 in med dalj{im~asom mletja je bila uporabljena hitrost 400 min -1 . Prahovi so bili hladno stiskani pod tlakom 750 MPa in nato sintrani pri 1000°C za 24 h. Preiskovali so vpliv razli~nega~asa mletja prahu na mikrostrukturo in na mehanske lastnosti porozne strukture z opti~nim mikroskopom, s SEM-in XRD-analizo ter dolo~evanjem mikrotrdote in mehanske nanoobdelave. Trdoto in modul elasti~nosti so izra~unali iz meritev odvisnosti med obremenitvijo in globino vtisa tristranske diamantne konice (po Berkovichu). Rezultati rentgenske difrakcije so potrdili prisotnost a in b faz. Skratka, poudariti je treba, da ima material hierarhi~no strukturo, ki je posledica faze mletja. Pregledana zrna so sestavljena iz mnogo manj{ih podzrn, katerih velikost se je zmanj{evala s podalj{evanjem~asa mletja.

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