3. Describe step-by-step brittle fracture of some metals and
ceramics with poor ductility and toughness. In discussion highlight
and use relevant terms such as transgranular, Chevron pattern and
others.
Text Book- The Science and Engineering of Materials,
Askeland et al. (seven edition
Describe step-by-step brittle fracture of some metals and ceramics
with poor ductility and toughness. In discussion highlight and use
relevant terms such as transgranular, Chevron pattern and
others.
Answer should jot exceds more than half a page. Thank you
Compare the martensite and tempered martensite in terms of the
phases they contain, ductility, strength and microstructure,
explain the reasons for the differences.
Regarding the fracture mechanism of metals, polymers and
ceramics
(a) Explain why FCC metals show a ductile fracture even at low
temperatures while BCC metals do not.
(b) What is crazing? What can you say about the Poisson’s ratio
of the crazed material?
(c) Generally, in ceramics, intergranular fracture is preferred
to cleavage fracture; however, in metals, transgranular fracture is
the preferred mechanism for brittle failure. Why? Use a physical
reason supported with an equation in your answer.
A) Explain the general responses of ceramics, metals and
polymers to mechanical and electrical loads in terms of both
primary and secondly chemical bonds
B) Classify the following materials as a polymer, metal,
ceramic, or composite: Boron Nitride, Bricks, Plexiglas, Concrete
and Manganese.
Briefly explain how each of the following influences the elastic
modulus of a semicrystalline polymer and why:
(a) Molecular weight
(b) Degree of crystallinity
(c) Sample crystallized under strong flow conditions