Problem 1. (as illustrations for 2.7)
A 95%Cu5%Zn (in at.%) brass electrical component has been made of powdered
metal and contains 10 vol.% of pores. Estimate the resistivity of brass component.
The resistivity of Cu may be taken as 17 nm.
The resistivit
2.7 Resistivity of isomorphous alloys and Nordheims rule What are the maximum atomic and
weight percentages of Cu that can be added to Au without exceeding a resistivity that is twice that of pure gold?
What are the maximum atomic and weight percentages o

Solution:
D = 0.37in. A0 =
D0 = 0.505in.
L0 = 2in. L = 2.32in.
a) =
4
D02
Fmax = 37 kN
A =
4
D2
Ffr = 34kN
Fmax
A0
b) eng =
c)
eng =
d) =
EL%
Ffr
A0
L L0
L0
tr =
Ffr
A
= ln(1 + eng )
tr
L L0
100%
L0
=
AR %
A A0
100%
A0

Solution:
= B exp(
trec
EA
)
1.2 c
Consider the semiconducting IIVI compound cadmium selenide, CdSe. Given the atomic masses of Cd and Se, find the
weight fractions of Cd and Se in the compound and grams of Cd and Se needed to make 100 grams of CdSe.
The atomic mass of Cd and Se are
1.2 Atomic mass and molar fractions
a.
Consider a multicomponent alloy containing N elements. If w 1 , w 2 , ., w N are the weight fractions of
components 1,2,., N in the alloy and M 1 , M 2 , ., M N , are the respective atomic masses of the elements,
sho
_
1.9 Kinetic Molecular Theory Calculate the effective (rms) speeds of the He and Ne atoms in the HeNe
gas laser tube at room temperature (300 K).
Solution
To find the root mean square velocity (vrms) of He atoms at T = 300 K:
The atomic mass of He is (f
Example_1
Example_2
[7]
[5]
[5]
Example_3
1. An 75 at % Cu25 at % Zn brass disk of 50 mm diameter and 4 mm thickness is used to conduct heat from a heat
Problem_1
Steel and brass specimens have been tested. The results of tension tests are compared
in the table and graph below.
a) What are the Young moduli of steel and brass?
b) What are the 0.2% proof yield strengths of steel and brass ?
c) What are the