Back to Search Start Over

TEM study on the vein-like grain boundary structures in nitrocarburized cool-work tool steels and its formation mechanism.

TEM study on the vein-like grain boundary structures in nitrocarburized cool-work tool steels and its formation mechanism.

Authors :
Chen, Wanglin
Zhang, Daoda
Yao, Dengcan
Meng, Xianna
Source :
Surface & Coatings Technology. Sep2017, Vol. 324, p376-381. 6p.
Publication Year :
2017

Abstract

Vein-like grain boundary (VLGB) structures commonly appear in the nitrided or nitrocarburized iron-based materials. Such VLGB structures are extremely bad for its mechanical properties. However, the formation mechanisms of the VLGB structures are still unclear. Here we employ transmission electron microscopy and electron probe X-ray microanalysis to reveal the detailed microstructures and the formation mechanism of the VLGB structure in nitrocarburized Cr12MoV cool-work tool steel at 540 °C and 580 °C. The VLGB structures entirely consist of orthorhombic (Cr,Fe) 7 C 3 phase, with high density of micro-twins and stacking faults, and specific crystallography relationship between the (Cr,Fe) 7 C 3 -typed VLGB structure and matrix is: (101) α //( 2 ¯ 4 ¯ 1 ¯ ) C + 7.5° and [ 1 ¯ 11] α //[ 1 ¯ 02] C. The formation of the (Cr,Fe) 7 C 3 -typed VLGB structures are closely associated with the C/Cr concentrations, elastic strain energy, low-energy interface and formation enthalpy of the VLGB structure. Similar interpretation is also carried out to illuminate the formation of the VLGB structures in the other nitrocarburized or nitrided alloying steels. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02578972
Volume :
324
Database :
Academic Search Index
Journal :
Surface & Coatings Technology
Publication Type :
Academic Journal
Accession number :
124113847
Full Text :
https://doi.org/10.1016/j.surfcoat.2017.06.007