Crsytallographic orientation analysis of cleavage facets adjacent to a fracture trigger in low carbon steel
Crsytallographic orientation analysis of cleavage facets adjacent to a fracture trigger in low carbon steel
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低碳钢断裂触发点附近解理面的晶体学取向分析
DOI：
10.1007/s10704-015-0014-5
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发表时间：
2015
影响因子：
2.5
通讯作者：
T.Tagawa
中科院分区：
文献类型：
--
作者：
S.Imamura;H.Muramoto;Y.Murata;Y.Shimada;Y.Kayamori;T.Tagawa
研究了低碳钢断裂韧性试样在解理裂纹触发点下的显微组织和晶体取向。刻蚀后的解理面SEM断口形貌显示，从触发点开始扩散的解理面脊之间的平面解理面被铁素体和珠光体之间的晶界所分割。即使不同的相界偶尔也不会在解理面上产生任何台阶和隆起，这表明该相界不是解理开裂的障碍。从该相界磨出的薄片样品的电子衍射分析表明，铁素体晶粒的晶体取向与相邻珠光体块中的铁素体晶粒的晶体取向一致。当珠光体块体中铁素体的晶体取向与相邻的铁素体晶粒对齐时，铁素体/珠光体边界对解理裂纹扩展不起局部阻力作用。
The microstructure and crystallographic orientation under a cleavage crack trigger point, which was detected on a fracture toughness specimen of low carbon steel, were investigated. SEM fractographs of an etched cleavage facet reveal that a flat cleavage facet between facet ridges spreading from the trigger point is divided by a grain boundary between ferrite and pearlite. Even a different phase boundary does not occasionally create any steps and ridges on the cleavage facet: it suggests this phase boundary is not an obstacle to cleavage cracking. Electron diffraction analysis for the thin foil sample milled out from this phase boundary demonstrates that the crystallographic orientation of the ferrite grain is consistent with that of the ferrite in the adjacent pearlite block. It is strictly examined that the ferrite/pearlite boundary does not act as a local resistance to cleavage crack growth when the crystallographic orientation of the ferrite in the pearlite block is aligned with an adjacent ferrite grain.