Deformation of metals, Other Engineering

Assignment Help:

Q. Explain the following with reference to deformation of metals:

                        (1) Preferred orientation

                        (2) Elastic after effect

                        (3) Bauschinger effect

Ans. (1) Preferred orientation: It is a condition of polycrystalline aggregate in which crystal orientations are not random under certain conditions the crystal is a metal tend to align themselves in a common axial direction. Such a direction is known as a preferred orientation.

       Preferred orientation occurs when certain crystallographic planes, tend to orient themselves in a preferred manner with respect to the direction of maximum strain.

(2) Elastic after effect: Consider a metal which is subject to sudden constant stress at a level below the elastic limit.

     After an initial instantaneous strain, the metal will gradually creep until the strain reaches an essentially value.

      If the load is removed suddenly, the strain drops instantaneously, but not at all a certain amount of strain still remains that solely decrease with time, approaching its original value. The time dependence of strain is called the elastic after effect.

(3) Bauschinger Effect: If in a metal the flow is started at certain stress intensity in one direction in one slip plane system, and subsequently the sign of the stress is reversed then flow in the reverse direction will initiate at a lower stress level.

       Let a material has the yield stress in tension as 'a' and the same in compression as 'x'. If is a new specimen of the same material is loaded in tension past the limit yield stress to 'b' along the path 'q, a, b' and then it is unloaded it will flow the path 'b, c'.

     If now, the specimen is subjected to reversed stress compressive stress the plastic flow will begin at the stress corresponding to point 'd' which is apparently lower than the original compressive yield stress of the material corresponding to point 'x'.

      Thus, while the yield stress in tension was increased by strain hardening from 'a' to 'b' the yield stress in compression is decreased from 'x' to 'd'. This effect is Bauschinger effect.


Related Discussions:- Deformation of metals

Aviation legislation - permit to fly, PERMIT TO FLY A Permit to Fly may...

PERMIT TO FLY A Permit to Fly may be issued to an aircraft that does not, for a variety of reasons, fully comply for a Certificate of Airworthiness. These reasons might be b

True or false, Beta coefficients and standard deviation may be used as indi...

Beta coefficients and standard deviation may be used as indicators of risk

Apu engine, APU Engine APU engines usually consist of a centrifugal com...

APU Engine APU engines usually consist of a centrifugal compressor and a radial turbine however, axial compressors and turbines may be added or used in their own right. Centrif

Qualitative risk assessment - fire protection engineering, Qualitative risk...

Qualitative risk assessment - fire protection engineering: NFPA 551 discusses the differences between qualitative risk assessment and quantitative risk assessment. Qualitat

Moulding materials, The commonly used moulding materials for mould making...

The commonly used moulding materials for mould making can be broadly classified into the following two groups :             (a) Metals : Including grey cast iron, steel and an

Microprocessor, software development cycle for 8086

software development cycle for 8086

Aeroengines - compressible flow, All fluids are to some extent compressible...

All fluids are to some extent compressible but gases show significant changes in density if pressure and/or temperature is changed. Some gas flows can be treated as being incomp

Creep, strain rate on creep

strain rate on creep

Bajaj electronics company, how would you judge the potential profits of Baj...

how would you judge the potential profits of Bajaj electronics on the first year of sales to booth plastics and give your views to increase the profit?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd