TY - JOUR

T1 - Algorithm for three-dimensional analysis of cleavage facet and its application for brittle fracture surface of steels

AU - Takano, Tachio

AU - Sumiyoshi, Hideshi

AU - Masuda, Chitoshi

PY - 1990

Y1 - 1990

N2 - Computer image processing technology has been applied to cleavage fracture surface analysis and an algorithm for the estimation of 3-dimensional cleavage facet boundaries and 3-dimensional facet areas has been developed. An angle αi,j between relative normal vectors of one mesh Pi,j and adjacent mesh plane Pi+1,j was calculated and the α1,j was compared to the threshold one αth. If αi,j is larger than αth and the αi+1,j calculated between the mesh planes P1+1,j and Pi+2,j along X axis is smaller than αth, the Pi+1,j mesh plane was the facet boundary. The same calculation was continued along both X- and Y-axes, and facet numbers being contained in the analyzed area were obtained. After the estimation of facet boundaries, 3-dimensional facet areas were calculated by dividing the 2-dimensional facet areas by cos βk which is the angle between average normal vector of facet and vertical vector. By this algorithm, the cleavage fracture surfaces were analyzed of JIS SS41 and HT80 steels and the effect of the threshold angles αth is discussed using the facet numbers estimated, the distribution of the values of α, and the 3-dimensional facet areas. The method is useful to analyze cleavage facet size and discuss the relationship between the cleavage fracture and microstructures such as ferritic grain size and prior austenitic grain.

AB - Computer image processing technology has been applied to cleavage fracture surface analysis and an algorithm for the estimation of 3-dimensional cleavage facet boundaries and 3-dimensional facet areas has been developed. An angle αi,j between relative normal vectors of one mesh Pi,j and adjacent mesh plane Pi+1,j was calculated and the α1,j was compared to the threshold one αth. If αi,j is larger than αth and the αi+1,j calculated between the mesh planes P1+1,j and Pi+2,j along X axis is smaller than αth, the Pi+1,j mesh plane was the facet boundary. The same calculation was continued along both X- and Y-axes, and facet numbers being contained in the analyzed area were obtained. After the estimation of facet boundaries, 3-dimensional facet areas were calculated by dividing the 2-dimensional facet areas by cos βk which is the angle between average normal vector of facet and vertical vector. By this algorithm, the cleavage fracture surfaces were analyzed of JIS SS41 and HT80 steels and the effect of the threshold angles αth is discussed using the facet numbers estimated, the distribution of the values of α, and the 3-dimensional facet areas. The method is useful to analyze cleavage facet size and discuss the relationship between the cleavage fracture and microstructures such as ferritic grain size and prior austenitic grain.

UR - http://www.scopus.com/inward/record.url?scp=0025067073&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0025067073&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0025067073

SN - 0915-1559

VL - 30

SP - 552

EP - 558

JO - Transactions of the Iron and Steel Institute of Japan

JF - Transactions of the Iron and Steel Institute of Japan

IS - 7

ER -