CBE30361 Lecture Notes - Lecture 13: Shear Stress, Single Crystal, Grain Boundary

62 views4 pages

byzantiumherring211

10 Feb 2016

School

Department

Chemical & Biomolecular Engr.

Course

CBE30361

Professor

Ruilan Guo

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Fcc slip occurs on {111} planes (close-packed) in <110> directions (close packed) Resolved shear stresses result from applied tensile stress (cid:2026) = (cid:1832) (cid:1827)(cid:1755)(cid:1755),(cid:1875)(cid:1860)(cid:1861)(cid:1855)(cid:1860) (cid:1861)(cid:1871) (cid:1872)(cid:1860)(cid:1857) (cid:1871)(cid:1860)(cid:1857)(cid:1853)(cid:1870) (cid:1871)(cid:1872)(cid:1870)(cid:1857)(cid:1871)(cid:1871) A is the cross-sectional area of the cylinder. F is the tensile force applied in the axial direction. Crss = critical resolved shear stress, which is the yield stress. If not, what stress is needed? (cid:2026) = 45 (cid:1839)(cid:1842)(cid:1853),(cid:2019) = 35 ,(cid:2038) = 60 (cid:2028) = (45)(cos(60))(cos(35)) = 18. 4 (cid:1839)(cid:1842)(cid:1853) 18. 4 (cid:1839)(cid:1842)(cid:1853) < 20. 7 (cid:1839)(cid:1842)(cid:1853),(cid:1871)(cid:1867) (cid:1872)(cid:1860)(cid:1857) (cid:1855)(cid:1870)(cid:1877)(cid:1871)(cid:1872)(cid:1853)(cid:1864) (cid:1875)(cid:1861)(cid:1864)(cid:1864) (cid:1866)(cid:1867)(cid:1872) (cid:1877)(cid:1857)(cid:1864)(cid:1856) Slip planes and directions varies from one grain to another. Thus, (cid:2028)(cid:3019) will vary from one grain to another. The grain with the largest (cid:2028)(cid:3019) yields first. This actually strengthens the materials against plastic deformation. Restricting or hindering dislocation motion makes the material stronger and harder. Barrier strength increases with increasing angle of misorientation. Smaller grain size more barriers to slip. Impurity atoms distort the lattice and generate lattice strains.

Related Questions

1. (30 points) From the accompanying XRD data (taken with Cu K-Î± radiation lambda = 1.5418â«), (a) determine the crystal structure (BCC, FCC or Simple cubic?) of material, (b) index each peak - assign (hkl), and (c) calculate the lattice parameter, a.

2Î¸: 43.16, 50.30, 73.99, 89.85, 95.03, 116.92, 136.59

(d) Can you guess what this material is?

2. (40 points) (a) Consider a monoclinic lattice in the direct space. Sketch (to scale) a portion of the direct space lattice in the plane defined by base vectors a1 and a2 (a portion of a {001} plane containing the origin; a1 = 2a2 = 4â«; gamma = 60 degrees ). Include lattice points 3,3,0 and -3,-3,0 and all other lattice points at least as close to the origin as these.

(b) Next sketch (to scale) the corresponding portion of the reciprocal lattice (plane containing hk0 type lattice points) and label the lattice points. Be sure to show the base vectors b1 and b2.

3. (30 points) On a copy of the reciprocal lattice sketched in problem 2 above, draw the Ewald sphere (circle) corresponding to an incident X-ray beam (lambda = 3Ã ) with So in the [110] direction. Terminate So/lambda (a radius of the Ewald sphere) on the origin. Will any diffracted beams of type hk0 be produced? Which ones?

Organic chem problems practice. some I don't know how to approad, some I had multiple answers in my head. Please help! :D

1.Which of the following is NOT a quality of good exercise attire?

a. Nonporous (watertight)

b. Nonrestrictive

c. Layered

d. Supportive

e. c and d

2.The resting heart rate

a. generally increases as fitness improves.

b. is influenced by stress, illness, and caffeine.

c. is best counted in the morning while youâre still lying in bed.

d. b and c

e. all of the above

3.âIndividual differences,â as it relates to exercise, means all of the following EXCEPT

a. Modifications may be needed to match an exercise program to a personâs needs.

b. The same program may not work for two different people.

c. Two people can be performing the same aerobic moves at the same speed but exercising with different amounts of effort (levels of intensity).

d. Participants should try to minimize their differences by imitating every movement of their instructor.

e. Personal preference may influence a personâs motivation toward an exercise program.

4.The recommended duration for the high-impact exercise portion of a class is

Select one:

a. 12-15 minutes

b. 20-30 minutes

c. 30-40 minutes

d. 45-60 minutes

e. 60-90 minutes

5. An exercise program may need to be modified when a person

a. is coming back from an injury

b. has a different fitness level than the one being demonstrated by the instructor

c. has a medical condition such as diabetes or chronic joint pain

d. is returning after an illness

e. all of the above

CBE30361 Lecture Notes - Lecture 13: Shear Stress, Single Crystal, Grain Boundary

Document Summary

Get access

Related Questions