3313Q3Sp02 - ENSC 3313, Spring 2002 Answer anv 4 auestions...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
!j Quiz3 Name ENSC 3313, Spring 2002 Answer anv 4 auestions onlv, 1 point each This is a Callister text figure. What ASTM grain size number does it correspond to, approximately? ~C The equation is N = 2n-l. N is the number of grains we J see in an area I" x 1 " at i OOx, n is then the ASTM 4 --,. number . " ." ~ , " -. . Because this grain size looks quite uneven, I'm going to take an area 2" x 2" and divide by 4. I get -48/4 and N~ 12. - . -- .. /87" . 12=2n-l, n~.4Ji,say4-5. .'(;C . ,; ~.I ~ .. ,-, " c . '-'""'"" '/' ) ~ - Photomicrograph of the surface 01 a polished and etched polycrystalline specimen of an iron-chrornium alloy in which the grain boundaries aooear dark. lOOx. The activation energy to foffi1 a vacancy in copper is 0.9 eV/atom. Boltzmann's constant is 8.62 x 10-5 eV/atom-K. Hence, what proportion of the copper lattice sites are vacant at 1000°C? -. N = N e-Qv/kT o --You surely appreciate that it is an exponential relationship and that the 'e' exponent is dimensionless. T is in Kelvin! N
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

3313Q3Sp02 - ENSC 3313, Spring 2002 Answer anv 4 auestions...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online