The Deformation Behavior Analysis and Mechanical Modeling of Step/Intercritical Quenching and Partitioning-Treated Multi
- PDF / 5,837,807 Bytes
- 13 Pages / 593.972 x 792 pts Page_size
- 14 Downloads / 192 Views
UCTION
MULTIPHASE design is an important strategy in developing new advanced high-strength steels (AHSS) that possess excellent strength and elongation.[1–3] A new heat treatment process termed quenching and partitioning (Q&P) has been proposed in the past for the development of multiphase AHSS steels with retained austenite (RA).[4] RA is stabilized by the depletion of carbon in the supersaturated martensite during the partitioning treatment.[5,6] In order to utilize the synergy between hard and soft phases, a final microstructure should have a matrix composed of ferrite and martensite with certain amount of RA after the steel is reheated to the intercritical temperature.[7] The overall deformation behavior will largely depend on the complex phase interaction between matrix phases and transformation-induced plasticity (TRIP) effect. Regarding the study of dual-phase steels, the selection criterion for different mechanical models relies on the phase interaction between ferrite and martensite, which affects the stress/strain partitioning[8] during HONGSHAN ZHAO, Ph.D. Student, and XUEJUN JIN, Professor, are with the State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China, and also with the Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China. Contact e-mail: [email protected] WEI LI, Lecturer, is with the Institute of Advanced Steels and Materials, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. LI WANG, Chief Engineer, and SHU ZHOU, Junior Engineer, are with the State Key Lab of Development and Application Technology of Automotive Steels, Baosteel Research Institute, Shanghai 201900, China. Manuscript submitted December 23, 2015. METALLURGICAL AND MATERIALS TRANSACTIONS A
deformation.[9–11] The issues of interest are whether the plastic deformation of martensite takes place,[12,13] and if so how the two phases deform relative to each other if the martensite yields.[14–16] The deformation behavior of martensite is said to be mainly dependent on its yield strength, the morphology, and distribution. These factors are determined by carbon content, which may change with martensite volume fraction[17] or the temper treatment,[18] the initial microstructure, and corresponding heat treatment.[11,19] As to the TRIP effect, the mechanical property enhancement may be related to the local strengthening of the matrix by the elastic accommodation of the transformation[20] or the second-phase hardening by the existence of continuous appearance of martensite.[21–23] Matrix near the transformation-induced martensite particles can be significantly strengthened by the increased dislocation density.[24] If RA located in/near the local softened region transforms timely, the matrix can deform continuously without local failure. However, RA transformation out of synchronization with the deformation does little improvement to the mechanical properties. On the other h
Data Loading...
