An Al-2.5% Cu alloy is solution-treated quenched, and overaged at 230 C to produce a stable microstructure. If the Q (Cu particles) as spheres with a diameter of 0.00009 cm and a density of 4.26 g/cm3, determine the number of precipitate particles per cm3 ?
I would be very grateful for any solution or any suggestion of solution hints as urgent as possible.
2006-12-27 10:22:16 · 3 answers · asked by tyrannior 1 in Science & Mathematics ➔ Engineering
You need to know that the primary phase of the alloy is essentially aluminum with the particles acting as the Theta phase.
density (g/cm3):
Cu= 9.0
Al=2.7
Alloy=2.86 (2.5% Cu, 97.5% Al)
Particles=4.26
Since the alloy is comprised of alpha and theta some combination of those phases must equal the overall alloy density. So:
2.86=4.26x + 2.7y
x+y=1
Solve for x and y, where x is the % of Theta phase and y = % alpha phase
Solving for this shows the % Theta phase.
Lets assume that we have 2.86 g of material (or 1cm3), this would mean that we have 0.286 g of theta phase. 0.286g of Theta has a volume of 0.067cm3.
using V=1.33(pi) r^3, a particle has a volume of 3.8e-13 cm3. So you need 1.77e11 particles to fill 0.067cm3.
the answer is 1.77e11 particles/cm3
(not accounting for rounding differences/errors)
2006-12-28 04:32:08 · answer #1 · answered by anza_1 3 · 0⤊ 0⤋
You have the percentage of Cu in the Al, only question is whether it's a volume fraction or a mass fraction. Either way, you should be able to arrive at how much Cu is within a cubic centimeter and go on from there
2006-12-27 10:27:04 · answer #2 · answered by arbiter007 6 · 0⤊ 0⤋
(12 )take this number an work it out!
2006-12-27 10:36:21 · answer #3 · answered by DJenks64 2 · 0⤊ 0⤋