A single crystal of aluminum is oriented for a tensile test such that its slip plane normal makes an angle of  28.1 with the tensile axis. Three possible slip directions make angles  of 62.4, 72.0, and 81.1 with the same tensile axis.

(a) Which of these three slip directions is most favored?
(b) If plastic deformation begins at a tensile stress of 1.95 MPa, determine the critical resolved shear stress for aluminum.

A) The slip direction that is favored among the three given is;

slip direction that makes an angle of 62.4°

B) The critical resolved shear stress for aluminum is; 0.80 MPa

We are given;

Angle made by slip plane normal; Ф = 28.1°

Possible values angles of slip directions; λ = 62.4°, 72.0° and 81.1°.

The slip will occur in the direction where (cosФ × cosλ) is a maximum.

Since cosФ is constant, then the largest value of cosλ will make  (cosФ cosλ) to be a maximum. Thus;

The largest value for cosλ was for λ = 62.4°

Thus, the slip direction that is favored is at the angle of 62.4° with the tensile axis.

B) The critical resolved shear stress is gotten from the equation;

τ_crss = ( cosФ × cosλ)

We are given;

Tensile stress; = 1.95 MPa

Plugging in the relevant values gives;

τ_crss = (1.95)[cos(28.1) × cos(62.4)]

τ_crss = 0.80 MPa

Read more about crystal structure at; link

a) the slip direction is at an angle of 62.4° with the tensile axis

b) Critical  resolved shear stress is 0.8 MPa

Explanation:

Given that φ = 28.1°,  while possible values for λ are 62.4°, 72.0°, and 81.1°.

a) Slip would occur in a direction where cos Ф and cos λ is maximum. To get the slip direction we choose the highest cos λ

Therefore:

cos(62.4) = 0.46

cos(72) = 0.31

cos(81.1) = 0.15

Therefore, the slip direction is at an angle of 62.4° with the tensile axis

b)

Given σ = 1.95 MPa

Critical  resolved shear stress () is given as:

the correct answer is c.stops after infancy and childhood.

myelin is the substance of the central nervous system (cns) that insulates nerve cell axons to increase the speed at which nerve impulse travels. myelination is a process of myelin formation. this process occurs postnatally, begins in the embryo during the midst of early development and finishes after birth.

unlike the threaded fasteners which are used to clamp the machine members, power screws are used to transmit power. common applications of power screws are: screw jacks: to lift weight. lead screw of lathe: for axial movement of tool and its precise positioning.