Microstructures of Ti-29Nb-13Ta-4.6Zr (TNTZ) aged at temperatures between 573 and
723 K after solution treatment at 1063 K have super fine omega phase, or both super fine alpha
and omega phases, respectively in beta phase with an average grain diameter of 20 µm. Plain fatigue
strength of TNTZ aged after solution treatment is much greater than that of as-solutionized TNTZ in
both low cycle fatigue and high cycle fatigue life regions. This is due to the improvement of the
balance of strength and ductility by the precipitation of alpha phase. Fretting fatigue strength of
TNTZ conducted with various heat treatments decreases dramatically as compared with their plain
fatigue strength in both low cycle fatigue and high cycle fatigue life regions. In this case, the
decreasing ratio of fretting fatigue life increases with increasing the small crack propagation area
where both the tangential force and frictional force at the contact plane of pad exist. In fretting
fatigue in air, the ratio of fretting damage (Pf/Ff), where Pf and Ff stand for plain fatigue limit and
fretting fatigue limit, respectively, increases with increasing elastic modulus. In fretting fatigue in
Ringers solution, the passive film on specimen surface is broken by fretting action in TNTZ, which
have excellent corrosion resistance, and, as a result, corrosion pits that lead to decreasing fretting
fatigue strength especially in high cycle fatigue life region, are formed on its surface.
Development of a Modular Fretting Wear and Fretting Fatigue Tribometer for Thin Steel Wires: Design Concept and Preliminary Analysis of the Effect of Crossing Angle on Tangential Force
