TY - JOUR

T1 - Microstructure-mechanical property relationships in ultrafine-grained NbZr

AU - Niendorf, T.

AU - Canadinc, D.

AU - Maier, H. J.

AU - Karaman, I.

AU - Yapici, G. G.

N1 - Funding Information: The German part of this study was supported by Deutsche Forschungsgemeinschaft, within the Research Unit Program “Mechanische Eigenschaften und Grenzflächen ultrafeinkörniger Werkstoffe”. The US part of the work was supported by the Boston Scientific Corporation, Northwest Technology Center, Inc. and by National Science Foundation Contract no. CMMI 01-34554, Materials Design and Surface Engineering Program, Directorate of Engineering, Arlington, Virginia.

PY - 2007/11

Y1 - 2007/11

N2 - The present paper reports on the microstructure-mechanical property relationships in an ultrafine-grained (UFG) niobium-1 wt.% zirconium (NbZr) alloy, a potential biomedical material, severe plastically deformed at room temperature utilizing equal channel angular extrusion (ECAE). Monotonic tensile and low-cycle fatigue (LCF) experiments were carried out on the NbZr samples processed along ECAE routes 8BC and 16E, along with extensive microstructure analysis. The important finding is that the NbZr alloy processed along ECAE routes that lead to a higher volume fraction of high-angle grain boundaries (HAGBs) exhibits a stable cyclic deformation response in the LCF regime. This stands in good agreement with prior studies on other materials, such as UFG interstitial-free steel, in which the stable fatigue behavior was associated with the dominance of HAGBs. The current results provide a venue for utilizing the UFG NbZr alloy in biomedical applications that require a combination of long-term durability, high strength and very good biocompatibility, where the latter is not altered by ECAE processing. Furthermore, for the first time, we present guidelines for optimizing processing parameters that define the microstructure-cyclic stability relationship in UFG alloys.

AB - The present paper reports on the microstructure-mechanical property relationships in an ultrafine-grained (UFG) niobium-1 wt.% zirconium (NbZr) alloy, a potential biomedical material, severe plastically deformed at room temperature utilizing equal channel angular extrusion (ECAE). Monotonic tensile and low-cycle fatigue (LCF) experiments were carried out on the NbZr samples processed along ECAE routes 8BC and 16E, along with extensive microstructure analysis. The important finding is that the NbZr alloy processed along ECAE routes that lead to a higher volume fraction of high-angle grain boundaries (HAGBs) exhibits a stable cyclic deformation response in the LCF regime. This stands in good agreement with prior studies on other materials, such as UFG interstitial-free steel, in which the stable fatigue behavior was associated with the dominance of HAGBs. The current results provide a venue for utilizing the UFG NbZr alloy in biomedical applications that require a combination of long-term durability, high strength and very good biocompatibility, where the latter is not altered by ECAE processing. Furthermore, for the first time, we present guidelines for optimizing processing parameters that define the microstructure-cyclic stability relationship in UFG alloys.

KW - Biomaterials

KW - Cyclic stability

KW - ECAE

KW - Fatigue

KW - Microstructure

UR - http://www.scopus.com/inward/record.url?scp=35248825132&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2007.08.015

DO - 10.1016/j.actamat.2007.08.015

M3 - Article

AN - SCOPUS:35248825132

VL - 55

SP - 6596

EP - 6605

JO - Acta materialia

JF - Acta materialia

SN - 1359-6454

IS - 19

ER -