Bissoy.com
Doctors Medicines MCQs Q&A

The yield strength of a material is 200MPa when the grain size is 80 micron. If the frictional stress is 80MPa, find the strength when the grain diameter is 160 micron?

The yield strength of a material is 200MPa when the grain size is 80 micron. If the frictional stress is 80MPa, find the strength when the grain diameter is 160 micron? Correct Answer 180 MPa

According to the hall-patch relationship: σo=σi+kD-1/2 -> 200=80+k(80)-1/2 -> k=1252 So at D=160 σo=80+1252(160)-1/2 σo=178.9 MPa.

Related Questions

Identify the correct statements from the following:
P. 0.2% yield strength of a material implies 0.2% of the yield strength.
Q. Von-Misses yield criterion implies that yielding occurs when the distortion energy reaches a critical value.
R. Radius of the cylinderical Von-Misses yield surface increases as the grain, size of a single phase material decreases.
S. Tresca's yield criterion gives a circular cylinderical surface in the space of the three principal stresses.
The figure below shows the cumulative size distribution of particles of a crushed mineral. 10 kg of this material is first passed through a sieve of size 400 micron and then through a sieve of size 300 micron. The weight of mineral (in kg ) that is retained on the 300 micron sieve is . . . . . . . .
Mineral Dressing in Metallurgy mcq question image
The largest size of immobilised segment of dislocation in a Frank Read (FR) source contained in a polycrystalline material is of the order of grain size. In a metal of 10 μm grain size, the shear stress required to operate such a FR source is 100 MPa. If the grain size in the same metal is reduced to 10 μm, the shear stress required to operate such FR source would be . . . . . . . . MPa.
If the specimen is deformed plastically beyond the yield stress in one direction, e.g., tension and then after unloading it is loaded in the opposite direction, e.g., compression, it is found that the yield stress is less than the original yield stress. This dependence of yield stress on direction loading is called ____________
In order to double its yield strength, the grain size of a steel of ASTM grain size number 2 should be changed to ASTM grain size number (neglect friction stress)
Which of the following types of particulate matter pollutants are used in the calculation of the Air Quality Index (AQI)? (A) TSP (Total Suspended Particles) (B) PM 10 (Particulate matters of size 10 micron or less) (C) PM 2.5 (Particulate matter of size 2.5 micron or less) (D) PM 1 (Particulate matter of size 1 micron or less) Choose the correct answer from the options given below:
A material with grain size of ASTM No.6 has a lattice frictional stress 100 MN/m2 and locking parameter (Hall-Petch constant) 0.10 MN/$${m^{\frac{3}{2}}}$$
Grain size of the material is approximately
Tresca or maximum-shear stress criteria assumes that yielding occurs when the maximum shear stress reaches a value of the shear stress in the uniaxial tension test. Assume the principal stress being σ1, σ2, σ3 where σ1 is largest, and σ3 is the smallest principal stresses. Find the value of minimum shear stress to cause yielding, given that yield stress in tension is equal to σo?
Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, σ = yield strength and E = modulus of elasticity)
Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, $$\sigma $$ = yield strength and E = modulus of elasticity)