Bruce Mayer, PE Registered Electrical & Mechanical Engineer BMayer@ChabotCollege

Engineering 45 MT2 Exam Review Bruce Mayer, PE Registered Electrical & Mechanical EngineerBMayer@ChabotCollege.edu

Paper Creep

Paper Creep Find a LINEAR equation, ε(t), that approximates the creep of paper over 1-100 minutes A. Dwan, “Paper Complexity And The Interpretation Of Conservation Research ”, Journal ofthe American Institute of Conservation, Vol. 26, No. 1, pp. 1-17), 1987

Draw “Good” Line, Find 2-pts 2.47% 2.16%

Lever-Law vs. T Problem • Pb-Mg Alloy → 45 wt% Pb • Quenched from Hi-Temp at Which The Alloy is a solid with Phase Fractions: • Wα = 65% and WMg2Pb = 35% • Find the Approximate Temperature from Which the Alloy was Quenched

Freeze-In Problem • “Freeze In • For Troom Equil 45

T for Pure α = 26.5%Pb • “Freeze in from 360C 360 25.6

Lever-Law vs. T Problem Ans

Prob 10.9 → Avrami Eqn • Given that A→P Transformation obeys the Avrami Eqn: • Given Xform Data • Then find the time Required for 95% Transformation

P10.9 MATLAB Solution >> Y1 = log(log(1/0.8)) Y1 = -1.4999 >> Y2 = log(log(1/0.4)) Y2 = -0.0874 >> X1 = log(280) X1 = 5.6348 >> X2 = log(425) X2 = 6.0521 >> P = [X1, 1; X2, 1] 5.6348 1.0000 6.0521 1.0000 >> Q =[Y1; Y2] Q = -1.4999 -0.0874 >> z = P\Q z = 3.3849 -20.5732 >> n =z(1) n = 3.3849 >> k = exp(z(2)) k = 1.1620e-009 >> t = ((log(1/.05))/k)^(1/n) t = 603.0849

Pb-Sn Solders

Bruce Mayer, PE Registered Electrical & Mechanical Engineer BMayer@ChabotCollege