Work

Influence of intercritical annealing temperature on TRIP/TWIP effect of retained austenite and tensile deformation mechanism of IQ&P steel

Year: 2024

Type: article

Abstract: The aim of this study was to investigate the effects of intercritical annealing temperature on stability of retained austenite and tensile deformation mechanism of intercritical annealing quenching and partitioning (IQ&P) steels. By varying the intercritical annealing temperatures (700 °C and 750 °C), the following results were observed. The microstructure of experimental steels was examined by scanning electron microscopy, X-ray diffraction, and transmission electron microscope. With the decrease of intercritical annealing temperature from 750 °C to 700 °C, the content of retained austenite is doubled, and the microstructure is obviously refined. The mechanical properties of the test steel were tested by tensile test . The results demonstrate that the sample annealed at 700 °C showed the best product of tensile strength and elongation, which was above 34 GPa⋅% (ultimate tensile strength : 1016 MPa, total elongation: 33.5%). The fracture structure and morphology of the tensile specimens were examined to explore the key factors affecting the strength and plasticity of IQ&P steel. During the tensile process, the specimens annealed at lower temperatures maintained a better Kurdjumov-Sachs orientation relationship between the γ and α phases . In addition, the combination of a uniform distribution of microscopic stress and strain, a smaller difference in hardness between the phases and increased activation of multiple slip systems allows a greater amount of retained austenite in the low-temperature annealed specimens to be continuously subject to the transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) effect during the tensile process. The refinement of the microstructure and retained austenite grains could occur TRIP and TWIP effects in a more sustainable way, ultimately leading to more excellent comprehensive mechanical properties of the 700 °C annealed test steels.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2024.10.073

Authors: Shaolong Zhang, Wen Zhou, Feng Hu, Kaiming Wu, Serhii Yershov

Institutions: Wuhan University of Science and Technology, State Key Laboratory of Refractories and Metallurgy

Language: English

Topic: Microstructure and Mechanical Properties of Steels

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,430

Funder: National Natural Science Foundation of China