J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (8): 1671-1680.DOI: 10.1016/j.jmst.2019.04.005

• Orginal Article • Previous Articles     Next Articles

Interfacial microstructure evolution and bonding mechanisms of 14YWT alloys produced by hot compression bonding

Liying Zhouab, Shaobo Fenga, Mingyue Suna*(), Bin Xua, Dianzhong Lia   

  1. a Shenyang National Lab. for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    b School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
  • Received:2019-02-15 Revised:2019-03-15 Accepted:2019-03-21 Online:2019-08-05 Published:2019-06-19
  • Contact: Sun Mingyue
  • About author:

    1Authors contributed equally to this work.

Abstract:

Hot compression bonding was first used to join oxide-dispersion-strengthened ferrite steels (14YWT) under temperatures of 750-1100°C with a true strain range of 0.11-0.51. Subsequently, the microstructure evolution and mechanical properties of the joints were characterized, revealing that the 14YWT steels could be successfully bonded at a temperature of at least 950 °C with a true strain of 0.22, without degrading the fine grain and nanoparticle distribution, and the presence of inclusions or micro-voids along the bonding interface. Moreover, the joints had nearly the same tensile properties at room temperature and exhibited a similar fracture morphology with sufficient dimples compared to that of the base material. An electron backscattered diffraction technique and transmission electron microscopy were systematically employed to study the evolution of hot deformed microstructures. The results showed that continuous dynamic recrystallization characterized by progressive subgrain rotation occurred in this alloy, but discontinuous dynamic recrystallization characterized by strain-induced grain boundary bulging and subsequent bridging sub-boundary rotation was the dominant nucleation mechanism. The nuclei will grow with ongoing deformation, which will contribute to the healing of the original bonding interface.

Key words: Oxide dispersion strengthened steels, Hot compression bonding, Dynamic recrystallization, Tensile property