This article presents a study of fatigue-crack propagation behavior in Nitinol, a 50Ni-50Ti (at. pct) superelastic/shape-memory alloy, with particular emphasis on the effect of the stress-induced martensitic transformation on crack-growth resistance. Specifically, fatigue-crack growth was characterized in stable austenite (at 120 8C), superelastic austenite (at 37 8C), and martensite (at 265 8C...

It is necessary to manage the fatigue crack growth (FCG) once those cracks are detected during in-service inspections. In this paper, a simulation program (FCG-System) is developed utilizing the commercial software ABAQUS with its object-oriented programming interface to simulate the fatigue crack path and to compute the corresponding fatigue life. In order to apply FCG-System in large-scale ma...

The very high cycle fatigue behavior (10-10 cycles) of Ti-6246 has been investigated using ultrasonic fatigue techniques. In this regime of fatigue (0.4-0.6σYS), only certain microstructural regions are susceptible to fatigue damage accumulation, and lifetimes are related to the distribution of fatigue critical microstructural neighborhoods. Three distinct categories of crystallographic crack i...

The role of moisture in affecting both intrinsic and extrinsic aspects of the fracture and fatigue-crack growth resistance of a polycrystalline alumina (99.5% pure, 25 lm grain size) has been examined in both moist and dry environments at ambient temperature. The intrinsic (crack-tip) toughness, deduced from measured crack-opening profiles, is found to be less than for a single crystal and is 3...

An evaluation of the fatigue crack resistance of human dentin was conducted to identify the degree of degradation that arises with aging and the dependency on tubule orientation. Fatigue crack growth was achieved in specimens of coronal dentin through application of Mode I cyclic loading and over clinically relevant lengths (0 ≤ a ≤ 2 mm). The study considered two directions of cyclic crack gro...

this paper presents a finite element analysis and its related experimental test of corrugated steel web beams subjected to fatigue loading. a particular focus in this study was set on the fatigue failure arising from the web-to-flange welded joint of the corrugated steel web beam. a detailed three-dimensional finite element model which explicitly includes the geometry of the web-to-flange welds...

The role of crack-tip shielding in in ̄uencing mixed-mode (mode I‡ II) fatigue-crack growth thresholds for large, through-thickness cracks in a Ti±6Al±4V turbine blade alloy is examined under high-cycle fatigue loading conditions, i.e., at a loading frequency of 1000 Hz in ambient temperature air for load ratios (Kmin=Kmax) of R ˆ 0:1±0.8. Techniques are developed to quantify crack-tip shielding...

Nowadays modification of metallic biomaterials which are used as implants for bone and hard tissues replacement is considered as an important subject. In the current study, corrosion fatigue properties of Ti-6Al-4V alloy investigated via Rotating-Bending standard test method and then, the results compared with the fatigue properties of the specimens tested in the same conditions. Scanning elect...

In situ ultrasonic fatigue with a cyclic frequency of 20 kHz was employed in an environmental scanning electron microscope (ESEM) to characterize fatigue crack formation and growth in the near alpha titanium alloy Ti–6242S. The role of environment on small fatigue crack initiation and growth was investigated in vacuum and in variable pressures of saturated water vapor, as well as in laboratory ...