Question

For high technological industries, you evaluate metals and ceramics beyond the Fe-c alloys to more costly applications. A. Select three alloying components for Ti alloys to give alpa+beta phases from simple solidification or peritectic reaction and beta+gamma phases from a eutectic reaction. B. What alloying elements should you seek for stainless steel to have a bar or plate with 50% austenite and 50% ferrite, with a significant martensitic phase, with reduction of sensitization and with reduction of pitting corrosion? C. Liquid Hf-Nb alloy infuses into a BC packed bed and reacts to form a HfB2-HfC- Nb3B4-Nb2C composite or the same boride-carbide precipitates embedded in a Hf-Nb alloy matrix. Determine the mass of Nb needed to give you suficient Nb,B, and Nb C in the metal matrix D. How much Ht is needed to produce an H-30 wt%Nb alloy at 3200°C for 4C. E. A hafnium-niobium melt contained in a graphite or carbon crucible (1 cm thick and 5 cm inner diameter) reacts to form an internal layer composed of HfC and NbC at the liquid Hf-Nb/C interface. The carbon seems to diffuse through the HIC at 20 μm/s05 and 7 um/sat 2300°C and 1800°C, respectively. The entire HiC/NbC-liquid Hf-Nb/C system is heated to 3200°C, will the HiC grow faster than NbC assuming the figure below gives the diffusion coefficient of carbon in cm2/s? 0.5 3

Answer 1

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