Abstract—

Using commercial low-alloy steel as an example, we have studied the nature of the increased scatter in impact toughness in the temperature range of the ductile-to-brittle (D–B) transition by multiple impact toughness tests and examined the microstructure of the steel by electron backscatter diffraction (EBSD). The results demonstrate that the scatter in the impact toughness of the low-alloy steel in the case of fracture in the temperature range of the D–B transition is due to toughness nonuniformity in the plastic zone. To assess the local toughness nonuniformity of the plastic zone in the microstructure of particular specimens fractured in the range of the B–D transition, we evaluated the percentage of the total length of ductile/brittle microcracks. We have demonstrated conceptual feasibility of developing a method for separating the contributions of local plastic deformation preceding and accompanying fracture for particular specimens in the range of the D–B transition using EBSD.

中文翻译：

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延性-脆性转变条件下低碳低合金断裂用冲击韧性的散点性质

摘要-

以商业低合金钢为例，我们通过多次冲击韧性测试研究了在韧性到脆性（D–B）转变温度范围内冲击韧性增加的散布性质，并检查了合金的微观结构。钢通过电子背散射衍射（EBSD）。结果表明，在D–B转变温度范围内发生断裂的情况下，低合金钢的冲击韧性有所分散，这是由于塑性区的韧性不均匀所致。为了评估在B–D转变范围内断裂的特定试样的微观结构中塑性区的局部韧性不均匀性，我们评估了韧性/脆性微裂纹总长度的百分比。