MCQOPTIONS
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MCQOPTIONS
This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Metallurgy knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What is the resolved shear stress, when dislocation density in metal is equal to 1012m-2? Given that shear stress needed in the absence of dislocation is 500MPa. Numerical constant is 0.3 and shear modulus is 80GPa, burger vector is 1 nm. |
| A. | 500MPa |
| B. | 550MPa |
| C. | 600 MPa |
| D. | 524 MPa |
| Answer» E. | |
| 2. |
Strain hardening due to ___________ process arises from short range force occurring over a distance of 5 to 10 atomic distance. This hardening can be overcome at finite temperatures with the help of thermal fluctuations, and therefore, it is temperature and strain-rate-dependent. |
| A. | dislocation cutting |
| B. | dislocation pile-up |
| C. | second phase particle |
| D. | alloying |
| Answer» B. dislocation pile-up | |
| 3. |
The formation of jogs in screw dislocations _________ its motion. Jogs in edge dislocations _________ its motion. |
| A. | restricts, do not restricts |
| B. | do not restricts, restricts |
| C. | restricts, restricts |
| D. | do not restrict, do not restrict |
| Answer» B. do not restricts, restricts | |
| 4. |
Cross slip can occur in both the edge dislocation as well as in screw dislocation. |
| A. | True |
| B. | False |
| Answer» C. | |
| 5. |
The interaction of dislocation does not result in ______________ |
| A. | jog |
| B. | kink |
| C. | dislocation threading |
| D. | slip |
| Answer» E. | |
| 6. |
Which of the following phenomena is responsible for the formation of sessile dislocation? |
| A. | Lomer-Cottrell barriers |
| B. | Frank read source |
| C. | Age hardening |
| D. | Dislocation jog and kink |
| Answer» B. Frank read source | |
| 7. |
The dislocation of low mobility that is produced by a dislocation reaction is called a ______ dislocation. |
| A. | sessile |
| B. | glissile |
| C. | screw |
| D. | edge |
| Answer» B. glissile | |
| 8. |
A zinc crystal is strained to point A, unloaded, and then reloaded in the direction opposite to the original slip direction:What is the reason for the drop in shear stress when loaded in the opposite direction? |
| A. | n<a href="https://www.sanfoundry.com/wp-content/uploads/2020/01/mechanical-metallurgy-questions-answers-plastic-deformation-single-crystal-deformation-twinning-q4.png"><img alt="Find the reason for the drop in shear stress when loaded in the opposite direction" class="alignnone size-full wp-image-265621" height="302" sizes="(max-width: 532px) 100vw, 532px" src="https://www.sanfoundry.com/wp-content/uploads/2020/01/mechanical-metallurgy-questions-answers-plastic-deformation-single-crystal-deformation-twinning-q4.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2020/01/mechanical-metallurgy-questions-answers-plastic-deformation-single-crystal-deformation-twinning-q4.png 532w, https://www.sanfoundry.com/wp-content/uploads/2020/01/mechanical-metallurgy-questions-answers-plastic-deformation-single-crystal-deformation-twinning-q4-300x170.png 300w" width="532"/></a> |
| B. | Back stress |
| C. | Strain hardening |
| D. | Increase in the number of slip system |
| E. | Slip plane reorientation |
| Answer» B. Back stress | |
| 9. |
Which of the following is not a source of dislocation multiplication? |
| A. | Condensation of the vacancy |
| B. | Frank read mechanism |
| C. | Emission from high angle grain boundary |
| D. | Annealing |
| Answer» E. | |
| 10. |
Inhomogeneous deformation of crystal results in regions of different orientation called deformation bands. Deformation bands have been observed in both fcc and bcc metals, but not in hcp metals. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 11. |
Among the given metal, which has the highest stacking fault energy? |
| A. | Aluminum |
| B. | Copper |
| C. | Brass |
| D. | Stainless steel |
| Answer» B. Copper | |