Fatigue Crack Growth and Fracture Toughness in a Dual Phase Steel: Effect of Increasing Martensite Volume Fraction

  • C. Perez Velasquez Grupo de Investigación IPMIM, Universidad Nacional de Colombia, Bogotá D.C. Colombia. Phone: +5713165000 (11214,11203)
  • D. Avendano Rodriguez Grupo de Investigación IPMIM, Universidad Nacional de Colombia, Bogotá D.C. Colombia. Phone: +5713165000 (11214,11203)
  • C. Narvaez Tovar Grupo de Investigación GNUM, Universidad Nacional de Colombia, Bogotá D.C. Colombia
  • L. Mujica Roncery Grupo de Investigación en Materiales Siderúrgicos e INCITEMA, Universidad Pedagógica y Tecnológica de Colombia, Boyacá, Colombia
  • R. Rodríguez Baracaldo Universidad Nacional de Colombia
Keywords: Dual-phase steel; Fracture toughness; XFEM; Crack fatigue growth

Abstract

Crack growth resistance in dual-phase steel was studied. The dual phase steel microstructure was modified through heat treatments to increase the martensite volume fraction from 10% to 40%. The as-received and heat-treated samples were evaluated using a uniaxial tensile test, fatigue crack growth test, and fracture toughness test. Extended Finite Element Method (XFEM) was used to simulate the crack growth in compact tension test specimens. The results showed that an increase in martensite volume fraction is an effective way to increase the fracture resistance under different load conditions, quasistatics and dynamic, increasing the fracture toughness, tensile strength and fatigue resistance of the heat-treated material. Presence of a highest content of martensite results in formation of an important number of secondary cracks during the fatigue crack growth, which slow down the crack propagation. Moreover, martensite generates a crack closure over the crack tip, making the propagation difficult due to the irregularities caused by the crack growth on the martensite. Finally, the computational load-displacement curves are in good agreement with the experimental data.  

Published
2020-10-06
How to Cite
Perez Velasquez, C., Avendano Rodriguez, D., Narvaez Tovar, C., Mujica Roncery, L., & Rodríguez Baracaldo, R. (2020). Fatigue Crack Growth and Fracture Toughness in a Dual Phase Steel: Effect of Increasing Martensite Volume Fraction. International Journal of Automotive and Mechanical Engineering, 17(3), 8086-8095. https://doi.org/10.15282/ijame.17.3.2020.02.0606