This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “Fractures in Ceramics”.
1. Which of the point is there in a stress strain curve for a ceramic?
a) Ultimate tensile strength
b) Fracture point
c) Limit of proportionality
d) Yield point
Explanation: The correct answer is fracture point. Unlike metals or non metals, ceramics just break which is reach the fracture point after a certain amount of strain.
2. Which of the following is correct
a) Aluminum oxide reaches fracture point before glass
b) Aluminum oxide reaches fracture point after glass
c) Aluminum oxide reaches fracture point at the same time as glass
d) They do not reach a fracture point
Explanation: Aluminum oxide reaches fracture point before glass. In aluminum oxide for a large amount of stress little strain is produced.
3. Which of the following is a flexural strength not dependent on?
b) Distance between supports
c) Specimen width
d) Length of specimen
Explanation: Flexural strength is dependent on the force applied on the specimen, distance between the supports, width of the specimen and the height of the specimen and hence it does not depend on the length of the specimen.
4. For edge flaws to occur which of the following should be the value of constant in stress intensity factor formula?
Explanation: The correct answer is 1.12. For an edge flaw to occur, the value of the constant in the stress intensity factor formula should be 1.12.
5. Which of the following can be the tensile strength of fused silica (SiO2)?
a) 110 MPa
b) 150 Mpa
c) 90 MPa
d) 80 MPa
Explanation: The range for the tensile strength of fused silica (SiO2) which is a ceramic is 110 MPa. Therefore only 110 Mpa is the correct answer.
6. For zircon for the same flaw size, the intensity factor is more than alumina.
Explanation: The above statement is true. For a given flaw size for example 50 micrometers, the intensity factor for zircon is 4.6 units and that of alumina is 3.7 units.
7. The largest constituent elements and flaws increase the flexural strength.
Explanation: The above statement is false. The smallest constituent element and flaws increase the flexural strength.
8. Which of the following shows the best fracture strength?
d) There fracture strength are not comparable
Explanation: Zircon shows the best fracture strength among the three elements, alumina, zircon and macor.
Sanfoundry Global Education & Learning Series – Materials Science.
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