on the nature of the yield point phenomenon

9781468418620:Yield Point Phenomena in Metals and Alloys

The remaining chapters deal, in turn, with the various alloys exhibiting yield point phenomena. Thus, chapter 2 on mild steel, is a more extensive study of quench and strain ageing, while Chapter 3 is on the refractory metals and discusses theories of the low-temperature strength.

Causes of the yield-point phenomenon in commercial

Results show that the yield point is caused by precipitate pinning. Furthermore, precipitation is enhanced by pre-strain, which can be introduced by elevated- temperature working, rapid cooling, or tensile elongation at room temperature. Aging is effective between 400 and 760 deg C, depending on the type of pre- strain, iron content, and texture. Chapter 12 Discontinuous and Inhomogeneous Phenomenon II:Strain Localization of Lueders Band After the upper yield point, there follows a plateau region called as the lower yield point where dislocations are free of the solute atmospheres. Nonhomogeneous deformation, such as Lueders bands appears and propagates through the sample. This is known as Lueders band along the stress-

Discontinuous Elongation/Yielding

Strain aging is a behavior, usually associated with the yield point phenomenon, in which the strength of a metal is increased and the ductility is decreased on heating at a relatively low temperature after cold working.2 The upper yield point returns with time and/or temperature, along with the fluting and stretcher strain it causes. In low Distortion and Yield Point of Molybdenum NatureIN a recent communication1, Dr. E. W. Fell refers to a letter from us2 and comments on the yield point of molybdenum wires after a certain heat-treatment in hydrogen followed by nitrogen, as shown

Double yield point - SlideShare

Jan 20, 2013 · We can also see the double yield point phenomenon in polythene. Under mechanical deformations, three grades of polythene which differ mainly in terms of branch content exhibit two yield points. The first yield point occurs at low applied strains and marks the onset of temporary plastic deformation; The second yield point occurs at higher strains and marks the onset of permanent plastic GATE Metallurgical Engineering:Yield point and strain agingYield point phenomenon localized heterogenous type of transition from elastic to plastic deformation produces a yield point in stress-strain curve. The load increases steadily with elastic strain, drops suddenly, fluctuates approximately at constant value of load, and then rises with further strain.

On the nature of the "double" yield point in Ti 50 Ni 25

Mar 01, 2017 · The anomalous phenomenon of the "double" yield point attributed with the "crystal amorphous state" phase transition during high-pressure torsion of Ti 50 Ni 25 Cu 25 alloy has been analyzed experimentally and theoretically. Satisfactory correlation between experimental data and theoretical hypothesis has been found. <P /> Relationship between Yield Point Phenomena and the Jan 01, 2012 · @article{osti_1033150, title = {Relationship between Yield Point Phenomena and the Nanoindentation Pop-in Behavior of Steel}, author = {Ahn, T. -H. and Oh, C. -S. and Lee, K. and George, Easo P and Han, H. N.}, abstractNote = {Pop-ins on nanoindentation load-displacement curves of a ferritic steel were correlated with yield drops on its tensile stress-strain curves.

Relationship between yield point phenomena and the

To investigate the relationship between pop-in behavior and yield point phenomena, four sets of tests were performed:just before, right after, 30 h after, and 3 weeks after the 6% tensile prestrain. For each of these conditions, a total of 64 indentations were made in an 8 × 8 array with 4 m spacing between the indents, as shown in Fig. 1 . What is yield point phenomenon? - AnswersDec 23, 2011 · A yield test is when a material is stretched, pulled, or pushed to its deformity point. The yield point is reached when the material will no longer return to its original structure.

Yield Point Phenomena in Metals and Alloys E. Hall

Yield Point Phenomena in Metals and Alloys. Exceptions to the rule are always interesting, and the anomalies in the stress-strain curves of mild steel and in many other metals and alloys have excited the curiosity of engineers and scientists for well over a hundred years. Yet it is only during the last twenty years that significant theoretical advances have been made, and the aim of this book has been to Yield Strength - Definition, Examples , Stress-Strain Yield Strength Definition Stress Strain Graph Stress Strain Graph Explanation Yield Strength Graph. What is Yield Strength? Whether an object is stubborn or malleable is decided by the yield strength. It is the point at which an object ceases to be elastic and becomes plastic. Yield strength helps us choose appropriate materials for the construction based on the requirement.

Yield Strength - Yield Point - Stress-strain Curve

Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible. Some steels and other materials exhibit a behaviour termed a yield point phenomenon. Yield strengths vary from 35 MPa for a low-strength aluminum to greater than 1400 MPa for very high-strength steels. Yield point mechanics BritannicaYield point, in mechanical engineering, load at which a solid material that is being stretched begins to flow, or change shape permanently, divided by its original cross-sectional area; or the amount of stress in a solid at the onset of permanent deformation.

Yield point phenomena in alpha brass and other face

The yield point phenomena were produced by various techniques which included ageing under stress, unloading and combinations of the two. The effects arising from ageing under stress are compared to experiments on repeated yielding. The particular results in brass are supported by various experiments with a range of face-centred cubic metals.The Yield Point Phenomenon (Methodology) :Materials The Yield Point Phenomenon.. Objective . Theory . Methodology . Results . The test is stopped soon after the the yield drop is observed and the sample is unloaded. New gauge length and the new area of cross-section are noted and the tensile test restarted. This time the test is conducted till fracture.