JH Payer

Bio: JH Payer is an academic researcher. The author has contributed to research in topics: Strain rate & Stress corrosion cracking. The author has an hindex of 1, co-authored 1 publications receiving 141 citations.

Brittle behavior of ductile metals during stress-corrosion cracking

Abstract: The transgranular stress-corrosion cracking of ductile alloys (and at least one pure metal) leads to a fracture appearance characteristic of cleavage. The experimental and theoretical background of this form of metal failure is reviewed. The discontinuous nature of crack growth in α-brass and copper is demonstrated using a combination of acoustic and electrochemical measurements. Short-range cleavage of ductile metals is shown to be theoretically possible provided the thin surface film which is responsible for crack initiation has the appropriate properties. The important parameters determining the effectiveness of films in initiating cleavage include the film-substrate misfit, the strength of the bonding across the film-substrate interface, the film thickness and the film ductility. Suitable combinations of these parameters which can lead to micro cleavage are determined by the state of coherency of the interface and the fracture toughness of the substrate. For example, if a ductile de-alloyed l...

Quantitative Assessment of Submodes of Stress Corrosion Cracking on the Secondary Side of Steam Generator Tubing in Pressurized Water Reactors: Part 1

Abstract: The work in this article is part of a project to develop a quantitative description of stress corrosion cracking (SCC) on the secondary side of pressurized water reactor (PWR) steam generator tubing based on existing information from operating plants and from laboratory experiments. This work is the second step in developing a predictive model for SCC on the secondary side. The first step involved developing a statistical framework into which dependencies of the various submodes of SCC can be inserted. The results of the present work will lead to quantitative descriptions of corrosion processes that, in turn, will be incorporated into the statistical framework. The chemistry of heat-transfer crevices will then be assessed to determine the proper inputs to the dependencies of the various submodes of SCC, and these will be connected to bulk environments. The modeling here is directed toward predicting the early occurrence of SCC that is too shallow to be detected by nondestructive examination (NDE)...

Linearly increasing stress test (LIST) for SCC research

Abstract: This paper presents a new testing apparatus for stress corrosion research. In this linearly increasing stress test (LIST) method, plain un-notched specimens are simultaneously exposed to an environment and subjected to an applied stress increasing linearly at a controlled rate. Experiments are repeated at various applied stress rates and the parameters measured include SCC initiation stress (the stress at which stress corrosion cracks start to propagate), fracture stress and average crack velocity. The LIST test is similar to the constant extension rate test (CERT) test, with the essential difference that the LIST test is load-controlled whereas the CERT test is displacement-controlled. The LIST test is particularly aimed at service conditions of loaded parts and structures; that is, service conditions described as load-controlled. This paper describes the design, construction and operation of the test apparatus and some typical results are given to illustrate its performance. Experiments have been conducted using as-quenched 3.5Ni-Cr-Mo-V turbine rotor steel specimens in aerated distilled water at 90 degrees C at stress rates varying from 0.00034 MPa s-1 to 2.08 MPa s-1.