Effect of heat treatment on microstructural and mechanical properties of molybdenum based PM ferrous alloys

Davoudnezhad, Ramona
In this study, the effect of different heat treatment processes on microstructural and mechanical properties of Distaloy-DH and Astaloy Mo (Fe-2Cu-1.5Mo) powders are investigated. Powder samples are sintered at 1120°C for 45 minutes in a sintering furnace under reducing atmosphere of: 10% H2 + 90% N2. After sintering, secondary heat treatments are performed on samples. Microstructural characterization of samples is done with optical and electron microscopy. Selective etching is utilized for determining the amount of bainite and martensite in samples. The Distaloy-DH samples yield approximately 1.9% less porosity than Astaloy Mo samples. In all specimens, pearlite, bainite and/or mixture of martensite and bainite phases are obtained based on the isothermal holding temperature or cooling rate from the austenite region. The study revealed that the specimens with martensitic and lower bainitic microstructure yield high TRS values with respect to either pearlitic or upper bainitic microstructures. Moreover, the lower bainitic structures yield similar or higher TRS values with respect to martensitic structures even at lower hardness values.


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The effects of lithium doping on the formation and properties of the T1-based superconductors have been studied. Lithium atoms up to around 3 mol.% have been added to the oxides of nominal composition Tl1.8Ba2Ca2.2Cu3Ox, and the usual solid-state reaction method has been applied. Lithium additions in the range 0.23-0.29 mol.% increase the fraction of the Tl-2223 phase and significantly improve the critical temperature of the samples. Higher amounts of lithium additions diminish the Tl-2223 phase, reduce the...
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Citation Formats
R. Davoudnezhad, “Effect of heat treatment on microstructural and mechanical properties of molybdenum based PM ferrous alloys,” M.S. - Master of Science, Middle East Technical University, 2016.