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采用高分辨率的径迹显微照相技术,研究了淬火硼钢中硼向奥氏体晶界偏聚的规律,定量地测定出跨过奥氏体晶界的硼的成分剖面图以及非平衡晶界偏聚的特征参量(晶界贫硼区宽度、晶界富集程度和富集带宽度)。试验表明,这种偏聚具有如下特征: 在偏聚晶界的两侧存在有一定宽度的贫硼区,晶界偏聚的硼是在冷却过程中由该区富集而来;这种偏聚对冷却速度很敏感,急速冷却可以抑制这种偏聚。冷却速度降低,晶界偏聚由连续的偏聚带,逐步发展为不连续的聚集直至明显地析出硼相,贫硼区宽度与冷却速度的平方根成反比;它的温度关系与晶界平衡偏聚预言相反,随淬火温度升高,晶界偏聚程度与贫硼区宽度增加。通过试验,论证了淬火钢中硼向奥氏体晶界的偏聚,是在冷却过程中发生的一种非平衡的晶界偏聚现象。
High-resolution track microscopy was used to study the rule of segregation of boron from austenite grain boundaries in quenched boron steel and to quantitatively determine the compositional cross-section of boron across the austenite grain boundaries as well as the non-equilibrium The characteristic parameters of segregation in the grain boundaries (the width of the boron-depleted zone, the enrichment of the grain boundary and the enrichment zone). Experiments show that this segregation has the following characteristics: there is a certain area of boron-depleted region on both sides of the segregation boundary, and boron segregated at grain boundaries is enriched from this region during cooling; Poly is very sensitive to cooling rate, rapid cooling can inhibit this segregation. Cooling rate decreased, the grain boundary segregation by the continuous segregation zone, and gradually developed into discrete aggregation until the obvious precipitation of boron phase, the width of the boron-depleted zone is inversely proportional to the square root of the cooling rate; its temperature relationship with the grain boundary equilibrium Conversely with the poly prophecy, as the quenching temperature increases, the degree of grain boundary segregation and the width of the boron-depleted zone increase. Through experiments, the segregation of boron from austenite grain boundaries in quenched steel is demonstrated, which is an unbalanced grain boundary segregation phenomenon during the cooling process.