Fatigue cracks in metals normally start at
A.Centre of the specimen
B.Core of the specimen
C.Ends of the specimen
D.Surface of the specimen
E.Any spot in the specimen
Category: Engineering Materials Mcqs
The phenomenon of ‘weld decay’ is associated with
A.Cast iron
B.Manganese steels
C.Aluminium alloys
D.Brass
E.Stainless steels
Hard steels and non-ferrous metal do not exhibit a definite yield point when pulled in the testing machine and for such cases a better measure of their elastic properties is defined by
A.Yield point stress
B.Yield point strain
C.Proof stress
D.Ultimate stress
E.None of the above
A Babitt is
A.A cutectic of iron and iron phosphide
B.A gadget for measuring volume
C.Antimony bearing lead or tin alloy
D.A measure of magnetic induction produced in a material
E.None of these
In Brinell hardness testing, while determining hardness of aluminium
A.Indenting ball of smaller diameter is used
B.Time of loading is reduced
C.Load on the indenter is reduced
Polystrene at room temperature is
A.Brittle
B.Malleable
C.Ductile
D.Soft
Which of the following is ‘acceptor’ impurity for semi-conductor?
A.Arsenic
B.Phosphorous
C.Boron
D.Antimony
E.All of the above
Steel cannot be hardened unless it is heated
A.Above the lowest critical point
B.Above the middle critical point
C.Above the highest critical point
D.Between the first and second critical point
E.Between the second and third critical point
Burger’s vector is
A.estimation of force9 of substit9utional atoms
B.a defect in crystall structure
C.a property of dislocations
D.None of the above
The process of reheating hardened steel to temperature below the lower critical temperature followed by any desired rate of cooling, is known as
A.Hardening
B.Spheroidizing
C.Tempering
D.Annealing
E.Normalizing
