Answer Happy

3) X-Ray diffraction (7 Points) Two stainless steel samples are brought into a material analysis lab for identification: It is known that one sample has a composition matching the AISI 3xx series, which contains mainly Fe, Cr and Ni and has an FCC crystal structure, whereas the other sample belongs to the AISI 4xx series, which contains only Fe and Cr and is characterized by a BCC crystal structure. a) which are the three types of cubic lattices? Draw a three-dimensional sketch of the aforementioned cubic lattices, positioning the atoms at the appropriate locations per lattice. Indicate the full names of the lattice types (1 point). The scientists carry out a test on both types of stainless steel with X-ray diffraction. The test results on one of their materials are shown schematically below. Only the first three peaks of the diffractogram are displayed. Assume that the test specimens are polycrystalline. The measurements are done with Cu radiation with a wavelength of 0.1542 nm. The measurement results are given in the table. Intensity 0.8 0.6 0.4 0.2 0 0 10 20 30 40 50 20 Peak number 1 2 3 60 70 80 20 44.0132 64.0008 80.9360 90 100 b) Which are the Miller indices {hk/) of the first three peaks of each of the cubic lattices drawn with a)? Explain your answer (1,5 points). c) Determine the crystal structure of the test specimen of the diffractogram shown above (1,5 points). d) Calculate the lattice parameter of the material (Tip: this is the length of the edge of the cube describing the cubic lattice) (1 point). e) Make a schematic drawing of the measurement setup with the x-ray source, the sample and the detector (1 point). f) Draw a simple cube (without atoms). Then select and draw 3 planes, belonging to one for each {hkl} that correspond to the peaks 1-3 shown in the table, (1 point). (Tip: make the cube large enough to show the planes clearly. You may draw the planes in separate cubes).