Homework assignment(released on April 28th,due on May 7th,2019) (Use an A4 sheet) 1.Below is a selected area electron diffraction pattern of a-Fe(bcc.a=0.2866nm).Find AL for the diffraction pattern,index the pattern and determine the zone axis. 2.If it is a polycrystalline Fe specimen in the above case,draw schematically the possible diffraction pattern with a scale bar. 3.Below is a selected area electron diffraction pattern from a polycrystalline region,taken from a cast steel block.There is concern that silicon may have been introduced into the casting as an impurity.Solve the pattern and index the rings.Is there any evidence for the presence of crystalline Si?
1 Homework assignment (released on April 28 th , due on May 7 th , 2019) （Use an A4 sheet） 1. Below is a selected area electron diffraction pattern of -Fe (bcc. a=0.2866nm). Find L for the diffraction pattern, index the pattern and determine the zone axis. 2. If it is a polycrystalline Fe specimen in the above case, draw schematically the possible diffraction pattern with a scale bar. 3. Below is a selected area electron diffraction pattern from a polycrystalline region, taken from a cast steel block. There is concern that silicon may have been introduced into the casting as an impurity. Solve the pattern and index the rings. Is there any evidence for the presence of crystalline Si?
Appendix Si source X-ray Cu-Kal 1.540598 2 Theta:20.000-140.000 EES geometry Bragg-Brentano.fixed slit. no anom.disp. 09 H K L 2Theta/deg d/A I/rel.F(hkl)I 111 28.447 3.13501 100.0059.60 220 47.311 191979 67.10 69.74 311 56.133 1.63721 39.94 46.21 222 58.868 1.56751 0.00 0.00 400 69.144 1.35750 10.70 60.10 IIS 331 76.392 1.24573 16.19 40.66 422 88.049 1.10839 23.14 53.66 511 94974 104500 10.17 36.46 333 94.974 1.04500 3.39 36.46 440106.735 0.95990 9.18 48.34 531 114.123 0.91784 18.41 32.91 TEE 442116.676 0.90500 0.00 0.00 620127.585 0.85856 20.62 43.78 00p 533136.944 0.82807 12.01 29.87 ITE 2
2 Appendix Si source : X-ray Cu-Ka1 1.540598 2Theta : 20.000 - 140.000 geometry : Bragg-Brentano. fixed slit. no anom. disp. H K L 2Theta/deg d/Å I/rel. |F(hkl)| ____________________________________ 1 1 1 28.447 3.13501 100.00 59.60 2 2 0 47.311 1.91979 67.10 69.74 3 1 1 56.133 1.63721 39.94 46.21 2 2 2 58.868 1.56751 0.00 0.00 4 0 0 69.144 1.35750 10.70 60.10 3 3 1 76.392 1.24573 16.19 40.66 4 2 2 88.049 1.10839 23.14 53.66 5 1 1 94.974 1.04500 10.17 36.46 3 3 3 94.974 1.04500 3.39 36.46 4 4 0 106.735 0.95990 9.18 48.34 5 3 1 114.123 0.91784 18.41 32.91 4 4 2 116.676 0.90500 0.00 0.00 6 2 0 127.585 0.85856 20.62 43.78 5 3 3 136.944 0.82807 12.01 29.87 022 113 222 004 133 224 115 044 135 244 026 335 a b c PowderCell2.0