Fatigue failure from internal defects in nickel base alloys

Fatigue failure from internal defects in nickel base alloys by Nathan Yu-kwong Kan Download PDF EPUB FB2

Age-hardenable alloys are generally more receptive to improving fatigue properties by ECAP, especially if solute and precipitate pinning of grain boundaries are utilised in a knowledgeable way to suppress grain coarsening during fatigue of an UFG alloy.

From: Fundamentals of Aluminium Metallurgy, Related terms: Aluminum Alloys; Nickel Alloys. Finding fatigue data in the Total Materia database.

Total Materia Extended Range includes the largest database of fatigue data and cyclic properties for thousands of metal alloys, heat treatments and loading conditions.

Both strain life and stress life parameters are given, with monotonic properties added for the reference, and statistical parameters and estimates where applicable.

The fatigue life of structural components and welds is decreased in LWR environments. The fatigue data in simulated BWR and PWR coolant for Ni-Cr-Fe alloys shows that the fatigue life of Inconel is comparable with that of Inconel (Fig.

).Also, the fatigue life of the Ni-alloy welds are comparable to those of the wrought alloys and in the low-cycle regime, that is. As most types of nickel-base alloys show mainly γ-phase (Belan (), Kobayashi et al. ()), which leads to a similar structure as found in austenitic chromium-nickel-steels, most available.

The high‐temperature fatigue tests seem to indicate that nickel base alloys can crack at 10 9 cycles at least. The powder N18 was tried with and without seeding of inclusions, in order to reveal the role of the inclusions in the gigacycle domain (Fig.

7).Cited by: Nickel-base superalloys, strengthened by a high volume fraction of Ni3Al precipitates, have been the undisputed choice for turbine discs in gas turbines as they exhibit the best available combination of elevated temperature tensile strength and resistance to low.

alloys are characterized by the best thermal fatigue resistance and better weldability than nickel-based superalloys. The third type of alloys also classi fi ed as a superalloys are nickel Author: Andrzej Nowotnik.

@article{osti_, title = {Comparison of fatigue detectability with several NDE methods}, author = {Kamimura, A and Isobe, Y and Aoki, K and Nakayasu, F}, abstractNote = {Detection of fatigue damage, preferably at an early stage, is essential to avoid component failures in nuclear power plants.

Consequently, establishing nondestructive evaluation (NDE) methods to measure accumulative. understanding of fatigue processes from the dis- ciplines of strain control fatigue and fracture me- chanics. The strain control approach is aimed primarily at fatigue crack initiation and early fa- tigue crack growth, while fracture mechanics concepts address the propagation of an existing crack to failure.

to failure between inspection intervals. Previous studies of several nickel- base, y' strengthened disk alloys have shown that the advanced, fine grain, high strength alloys possess relatively poor fatigue crack propagation resist- ance at turb!ne disk rim temperatures, particularly when the fatigue cjcleFile Size: 3MB.

Two fine-grain nickel-base alloys, Inconel (DA) and René 95, were identified as potential candidates to exhibit near-threshold creep.

A series of constant-Kmax fatigue crack growth tests were performed on these alloys to determine if these fine-grain nickel-base alloys are susceptible to a near-threshold creep mechanism.

∆K (MPa√m)Cited by: 1. The fatigue properties of the precipitation-hardened, nickel-base alloys, such as InconelIncoloy and Waspaloy, are significantly improved by a thermomechanical processing technique involving the generation of an intermetallic pinning phase, such as a spheriodal eta phase or an overaged gamma prime phase, with subsequent recrystallization to provide a uniform microstructure having a Cited by: Proceedings of the Fifth International Conference on the Effect of Hydrogen on the Behavior of Materials sponsored by the Structural Materials Division (SMD) Mechanical Metallurgy and Corrosion & Environmental Effects Committees of The Minerals, Metals & Materials Society held at Jackson Lake Lodge, Moran, Wyoming, September @article{osti_, title = {New knowledge about 'white spots' in superalloys}, author = {Jackman, L A and Maurer, G E and Widge, S}, abstractNote = {In Aprilthe first in a series of workshops was held to discuss ways in which the gas turbine industry could better understand defects in nickel-base superalloys.

The group's primary objective was to better define, and expand knowledge. FATIGUE BEHAVIOR AND FAILURE MECHANISMS OF DIRECT LASER DEPOSITED INCONEL Alexander S. Johnson 1, Shao Shuai, Nima Shamsaei2,*, Scott M. Thompson2, Linkan Bian3 1Center for Advanced Vehicular Systems (CAVS), Mississippi State University, MS 2Department of Mechanical Engineering, Auburn University, Auburn, AL 3Department of Industrial and.

This paper reviews what is known about the fatigue behavior of nickel-base superalloys and suggests methods for improving their properties. Low-temperature crack initiation occurs preferentially at microstructural defects such as pores and brittle phases in cast materials and at defects such as brittle phases and annealing twin boundaries in Cited by:   The ratio for fatigue-to-torsion incidence in clinically separated instruments was reported to be ; whereas some studies have reported that torsional failure is the predominant mode.

Torsional failure was more important in the present study. Low-cycle fatigue process needs at least 10(4) cycles of stress to occur. Thus, less rotating Cited by: 6. Fatigue Properties The name “fatigue” is based on the concept that a material becomes “tired” and fails at a stress level below the nominal strength of the material.

The facts that the original bulk design strengths are not exceeded and the only warning sign of an impending fracture is an often hard to see crack, makes fatigue damage.

The first part of the book explains the origin of the data, fatigue testing and data analysis procedures, and provides guidelines for the use and interpretation of the data. Detailed discussions are included on the effect of temperature, production process variables, shape, orientation, and joining and finishing technologies on aluminum alloy.

Abstract. In turbo-engines nickel base alloys are used for disks and rotors in the high-pressure compressor and turbine section. Whereas in large jet engines disks are made from wrought or powder-metallurgical materials, in small engines and turbo-chargers low-priced cast integral rotors are : Joachim W.

Bergmann, Paul Heuler, Michael Vormwald. The effects of a MCrAlY coating on low-cycle fatigue (LCF) behavior of directionally solidified (DS) nickle-based superalloy DZ were investigated.

Before the fatigue testings, the specimens were pre-exposed in high-temperature hot corrosion (HTHC) environment generating by a burner rig at °C.

The results show that the coating in hot corrosion condition has beneficial effects Author: Hong-Yu Qi, Ji-Shen Yang, Xiao-Guang Yang, Shao-Lin Li, Li-Qiang Ma.As discussed in chapters 2 and 3, most hot structures are fabricated from superalloys that have been tailored to meet the demands of turbine engine operation.

Specific solutions to problems encountered under one set of operational conditions are often in conflict with those encountered under another.A load of insufficient magnitude to cause failure in a single application may lead to failure if it is removed and reapplied repeatedly.

This mechanism of failure is known as fatigue. In unwelded metals and alloys the failure process consists of initiation of microscopic cracking, frequently at a surface feature such as a change of section.