TY - JOUR
T1 - Application of electron backscatter diffraction (EBSD) to fracture studies of ferritic steels
AU - Davies, PA
AU - Novovic, Milorad
AU - Randle, V
AU - Bowen, Paul
PY - 2002/3/1
Y1 - 2002/3/1
N2 - The application of electron backscatter diffraction (EBSD) to fracture studies has provided a new method for investigating the crystallography of fracture surfaces. The crystallographic indices of cleavage planes can be measured both directly from the fracture surface and indirectly from metallographic sections perpendicular to the plane of the adjoining fracture surfaces. The results of direct individual cleavage facet plane orientation measurements are presented for carbon-manganese (C-Mn) and low-alloy Mn-Mo-Ni (similar to ASTM A553 type-B). Pressure vessel steel weld metals, obtained from fracture surfaces of Charpy impact test specimens fractured at various test temperatures and for an ultra-low carbon steel (Fe-0.002C-0.058P) fractured at -196degreesC by impact. In addition to the direct measurement from the fracture surface, cleavage facet orientation measurements for the ultra-low carbon steel were complemented by the results obtained from the metallographic sections. Fractographic observations revealed that cleavage fracture is accommodated by a microvoid coalescence fracture micromechanism, which was induced by decohesion of second phase particles (inclusions). The correlation between the direct and indirect methodologies shows that the cleavage facet planes are dominated by the {001} plane orientations, and indicated that even when information concerning the full five degrees of freedom is inaccessible, the cleavage facet plane could still be determined. Finally, the advantages and disadvantages of direct orientation measurements from the fracture surface and indirectly by a destructive sectioning technique are discussed.
AB - The application of electron backscatter diffraction (EBSD) to fracture studies has provided a new method for investigating the crystallography of fracture surfaces. The crystallographic indices of cleavage planes can be measured both directly from the fracture surface and indirectly from metallographic sections perpendicular to the plane of the adjoining fracture surfaces. The results of direct individual cleavage facet plane orientation measurements are presented for carbon-manganese (C-Mn) and low-alloy Mn-Mo-Ni (similar to ASTM A553 type-B). Pressure vessel steel weld metals, obtained from fracture surfaces of Charpy impact test specimens fractured at various test temperatures and for an ultra-low carbon steel (Fe-0.002C-0.058P) fractured at -196degreesC by impact. In addition to the direct measurement from the fracture surface, cleavage facet orientation measurements for the ultra-low carbon steel were complemented by the results obtained from the metallographic sections. Fractographic observations revealed that cleavage fracture is accommodated by a microvoid coalescence fracture micromechanism, which was induced by decohesion of second phase particles (inclusions). The correlation between the direct and indirect methodologies shows that the cleavage facet planes are dominated by the {001} plane orientations, and indicated that even when information concerning the full five degrees of freedom is inaccessible, the cleavage facet plane could still be determined. Finally, the advantages and disadvantages of direct orientation measurements from the fracture surface and indirectly by a destructive sectioning technique are discussed.
KW - fracture
KW - cleavage
KW - fractography
KW - crystallographic facet analysis
KW - electron backscatter diffraction (EBSD)
UR - http://www.scopus.com/inward/record.url?scp=0036098496&partnerID=8YFLogxK
U2 - 10.1046/j.1365-2818.2002.00998.x
DO - 10.1046/j.1365-2818.2002.00998.x
M3 - Article
C2 - 11996192
SN - 1365-2818
SN - 1365-2818
SN - 1365-2818
SN - 1365-2818
SN - 1365-2818
SN - 1365-2818
SN - 1365-2818
VL - 205
SP - 278
EP - 284
JO - Journal of Microscopy
JF - Journal of Microscopy
IS - 3
ER -