Dynamic Tensile Behavior of Fiber Laser Welds of Medium Manganese Transformation-Induced Plasticity Steel
- PDF / 3,749,440 Bytes
- 11 Pages / 593.972 x 792 pts Page_size
- 61 Downloads / 219 Views
TION
REDUCED fuel consumption and greenhouse gas emissions, along with stricter safety regulations, acted as strong driving forces for development of advanced high strength steels (AHSSs) in recent years. Among a wide range of alloying systems, Mn-containing steels with stabilized austenite phase received a great deal of attention from researchers and the automotive industry due to the materials’ superior combination of strength and ductility. The low-alloy transformation-induced plasticity (TRIP) steels, which are generally referred to as the first-generation AHSSs, possessed up to 2.5 wt pct Mn.[1–7] Tensile strength up to 1100 MPa was achieved in the low-alloy TRIP steels through the deformation-induced transformation of the martensite from the metastable retained austenite (cR) phase.[3,6,8,9] However, the growing requirements to increase automobile
M.H. RAZMPOOSH, E. BIRO, and Y. ZHOU are with the Centre for Advanced Materials Joining, Department of Mechanical & Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 Canada Contact e-mail: [email protected] F. GOODWIN is with the International Zinc Association, Durham, NC 27713. Manuscript submitted September 13, 2018. Article published online May 23, 2019 3578—VOLUME 50A, AUGUST 2019
structural component strength (> 1 GPa) resulted in the development of second-generation AHSSs such as high-Mn twinning-induced plasticity (TWIP) steels. Several studies[10–14] have shown that a fully austenitic structure containing Mn greater than 15 wt pct could achieve a superior combination of strength and ductility. In TWIP steels, the mechanical twin nucleation and growth mechanism led to a dynamic Hall–Petch effect.[10] However, cost efficiency and manufacturing challenges due to the high alloy content in TWIP steel grades hindered their further development. Aside from the manufacturing challenges, poor weldability and high susceptibility to the liquid metal embrittlement limited the commercial application of TWIP steels in the automotive industry.[12,15–18] Current studies have mainly focused on balancing industrial feasibility, cost efficiency, and fulfillment of the strength-ductility requirements by using steel grades made with reduced Mn content. In line with these efforts, medium-Mn TRIP steel is a new class of TRIP steels (referred to as third-generation AHSS), which have been developed recently.[19–22] The improved combination of strength and ductility along with the cost-effective manufacturing introduced medium-Mn TRIP steel as a promising candidate for a wide range of automotive structural components such as B pillars and door reinforcements.[17,19–21]
METALLURGICAL AND MATERIALS TRANSACTIONS A
Medium-Mn TRIP steels are made using long intercritical holding times. This results in significant partitioning of Mn from the ferrite to the austenite, which results in high stability of the austenite phase and a subsequent active TRIP effect.[19,22–27] Several researchers focused on Fe-(5 to 12)Mn-(0.1 to 0.2)C alloy design, wh
Data Loading...
