Study On Hot Deformation Behavior And The Microstructure Of TZC Alloy

Currently molybdenum and molybdenum alloy products can not be compared with foreign competitors. Product category is uneven. Molybdenum and molybdenum alloy products without system molding be in primary and low level of molybdenum alloy industry chain. This subject is the branch of project of Molybdenum and molybdenum alloy product characteristics and processing performance study. The main objective of this project is to determine the optimum density, processing technology of molybdenum and molybdenum alloy,determine the processing characteristics of products and quality standard of molybdenum and molybdenum alloy, and the test of molybdenum and molybdenum alloy products, in order to obtain the actual machining process.In this paper, with the aids of OM, EPMA, TEM and EBSD, the hot deformation behavior, evolution of the microstructure and softening mechanisms of TZC alloy have been studied on thermal simulator testing machine. The high temperature deformation characteristics have been analyzed and provide a theoretical reference for the thermal processing technology. The conclusions were shown as follows:(1) The true stress-true strain curve of TZC alloy was drawn using the data selected, and the characteristics of the curve were analyzed. The influence of hot deformation parameters on flow stress of TZC alloy was analyzed. By comparing the different deformation resistance models, a new hyperbolic sine constitutive equation has been established using the parameters of Zener-Holloman,and we calculated the material constants and hot deformation activation energy.(2) Through the metallographic observation photos that obtained from the microstructure after water quenching,the test discovered the influence of hot deformation parameters on the microstructure of TZC alloy. The test discovered the conditions of dynamic recovery for TZC alloy through TEM. The test also discovered the conditions and the mechanism of the dynamic recrystallization through EBSD and OM photos. At the grain boundary it was continuous dynamic recrystallization;(3) Analysis showed that:the second phase in TZC alloy elements is Ti, Zr, O, C. Mainly in the larger grain size ZrxOy、(Mo, Ti, Zr)xOy and MoxCy and the grain size is very small dispersion (Mo, Ti, Zr)xCy carbides form.