Question

2. A steel bar 100 mm long and having a square cross section 20 mm on an edge is pulled in tension with a load of 89,000 N and experiences an elongation of 0.10 mm. Assuming that the deformation is entirely elastic, calculate the elastic modulus of steel. Give your answer in GPa. 3. A zinc single crystal is being pulled in tension with the normal to its basal plane (0001) at 60° to the tensile axis and the slip direction [1120] at 40° to the tensile axis. What is the resolved shear stress, T, acting in the slip direction when a tensile stress of 0.690 MPa is applied? 4. An alloy is evaluated for potential creep deformation in a short-term laboratory experiment. The creep rate & is found to be 1% per hour at 800 °C and 5.5 x102 % per hour at 700 °C. (a) Calculate the activation energy for creep in this temperature range. (b) Estimate the creep rate to be expected at a service temperature of 500 °C. (c) What important assumption underlies the validity of your answer in (b)? 5. A cylindrical specimen of a hypothetical metal alloy is stressed in compression. If its original and final diameters are 30.00 and 30.04 mm, respectively, and its final length is 105.20 mm, compute its original length if the deformation is totally elastic. The elastic and shear moduli for this alloy are 65.5 and 25.4 GPa, respectively.

Answer 1

020 Grens Length L= 100mm Area 20x20 min Lood p = 83.000 Sl 0.1m : To be find Elastic modules fi! * Deformation is entirely Plastico! SV According to hook's law n t he ६ ( surah) Ga shoes E- strain T=EE E = young modules let force = p them oraz and Strain & Change fa 29000 X 100 20% 20% 0.1 N mm 44 5000M 2 mm 222 SOON mmm loome - Jo pa f = su se sada I f= 222.56fa

& Girena &, (strain omale) = 1% W- 1073K $ Temperature (Ti) = 800+273 = Ex = S-5810?v./m. Tz = 700 +273: 973K cas Activation en dhe energy reg: en = kena l Ke Boltziren Gratant a R= Charecterstic Gas Compound So I = Kent ce te raad -=803145TK 5.5970's Kerl sou wot) eg. O Dirided by eg D > smo o colorows] exp ( 10.18 ex 892019 Ox() 808915) In 10-18 = -4.12181649 + 1-29629x104 dig = 0.115X15YQ @ = 25.22X10 I Q = 252.2 Kb male

25-22X104 e Greep rate at sove T= 500+ 273 27734. Erkel F ) ©: 1.380649 { : 1.9541040 12 = 1.25 X10 That equation was wed only for steady state (Secondary regime 8:314 x 793 | @ such as Neek @ Neglecting in homogeneity that micht arise 28 → Initial Dia = 30.00 mm final Dia a 80.04 mm Final lugth: 10s-20 mm orginal lngth= ? Elastic modulo E = 65.5 6 Pa Shear module G = 25.4 afa E = 26 (1+1). 65.5 = 2495:4(1+r) y = 0.209 lateral strain - 4 = Poisson satis • Poisson's ration - linear strain limeur Atraer = - Sold So - 104 04 =-46X10 =-46*103 80 X 289

= 104.71 &• тм | Дедај» lodgind Thoo. | | 1 X 2.5- | X9) - ? - 5 тура на лh oh o 1