Structure-property relationship of cast Ti-Nb alloys.
The present work is a study of the microstructure, mechanical properties and corrosion behaviour of a series of binary Ti-Nb alloys with Nb contents up to 35 wt%, with emphasis placed on the structure-property relationship of the alloys. The results indicate that crystal structure and morphology of the Ti-Nb alloys are sensitive to the Nb content. The cast c.p. Ti has a hexagonal alpha phase with a lath type morphology. The alloys containing 15 wt% or less Nb are dominated by a hexagonal alpha' phase with an acicular, martensitic structure. When containing 17.5-25 wt% Nb, the alloys are primarily comprised of an orthorhombic alpha" phase. With 27.5 wt% Nb, metastable beta phase starts to be retained. With Nb contents higher than 30 wt%, the equi-axed beta phase is almost entirely retained. Small amounts of omega phase are detected in alloys containing 27.5 and 30 wt% Nb. Among all present alloys, Ti-10Nb and Ti-27.5Nb exhibit the highest strengths, while the alpha"-dominated (17.5 and 20Nb) and beta-dominated (> 30Nb) alloys have the lowest moduli. All Ti-Nb alloys show excellent corrosion resistance in Hank's solution at 37 degrees C. From the present data, the microhardness, bending strength and modulus of the various phases in Ti-Nb alloys are compared and tentatively summarized as follows: Microhardness: omega > alpha' > alpha" > beta > alpha (c.p. Ti) Bending strength: omega > alpha' > alpha" > beta > alpha (c.p. Ti) Bending modulus: omega > alpha (c.p. Ti) > alpha' > alpha" > beta
Lee
C M
CM
Department of Materials Science and Engineering, National Cheng-Kung University, Tainan, Taiwan.
Ju
C P
CP
Chern Lin
J H
JH
D003343:Corrosion; D003461:Crystallography; D003722:Dental Alloys / Q000737:chemistry*; D004548:Elasticity; D006244:Hardness; D008422:Materials Testing; D009556:Niobium / Q000737:chemistry*; D018583:Pliability; D013329:Structure-Activity Relationship; D014025:Titanium / Q000737:chemistry*
D003722:Dental Alloys; D009556:Niobium; D014025:Titanium