A,B,C,D,E and F are the elements. Consider we need to study three binary systems which are...

 

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A,B,C,D,E and F are the elements. Consider we need to study three binary systems which are A-B, C-D and E-F for experimental reasons. Following information is also given: Atomic radius of A largely greater than B atom. Atomic radius of C atoms almost equal to D atoms. Atomic radius of F atoms greater than E atoms. B atoms has a limited solid solubility in A leading alpha phase and addition of A atoms to B forms beta phase and no intermetallic forms in this binary system. C and D forms solid solution in all proportions leading gamma phase. E and F have very limited solid solubility in each other and forms E₂F3 in F reach regions, E₂F compound in E reach regions. All the elements are roughly similar melting points. A)We need to create diffusion couples for these binary systems. Using your physical metallurgy knowledge explain how to prepare three diffusion couples for diffusion tests from these materials (10p) B) Thank you, we have perfect diffusion couples for the tests now. We are going to test them at high temperatures in solid state. To do that we keep them in a furnace in an inert atmosphere for a very long period of time. Please draw the diffusion couples before and after the test and mention the name and regions of newly formed phases in the approximate positions. (18) C) For each system (A-B, C-D and E-F) explain the expected type and mechanisms of the active diffusion during this test (6p). A,B,C,D,E and F are the elements. Consider we need to study three binary systems which are A-B, C-D and E-F for experimental reasons. Following information is also given: Atomic radius of A largely greater than B atom. Atomic radius of C atoms almost equal to D atoms. Atomic radius of F atoms greater than E atoms. B atoms has a limited solid solubility in A leading alpha phase and addition of A atoms to B forms beta phase and no intermetallic forms in this binary system. C and D forms solid solution in all proportions leading gamma phase. E and F have very limited solid solubility in each other and forms E₂F3 in F reach regions, E₂F compound in E reach regions. All the elements are roughly similar melting points. A)We need to create diffusion couples for these binary systems. Using your physical metallurgy knowledge explain how to prepare three diffusion couples for diffusion tests from these materials (10p) B) Thank you, we have perfect diffusion couples for the tests now. We are going to test them at high temperatures in solid state. To do that we keep them in a furnace in an inert atmosphere for a very long period of time. Please draw the diffusion couples before and after the test and mention the name and regions of newly formed phases in the approximate positions. (18) C) For each system (A-B, C-D and E-F) explain the expected type and mechanisms of the active diffusion during this test (6p).

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A Creating Diffusion Couples AB System Given that B atoms have limited solid solubility in A you can prepare a diffusion couple by taking two small pi... View the full answer