Identical mechanism of isochronal and isothermal embrittlement in Ni(Bi) alloy: Thermo-induced non-equilibrium grain-boundary segregation of Bi
Identical mechanism of isochronal and isothermal embrittlement in Ni(Bi) alloy: Thermo-induced non-equilibrium grain-boundary segregation of Bi
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DOI：
10.1016/j.apsusc.2015.02.068
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发表时间：
2015-05
影响因子：
6.7
通讯作者：
Lei Zheng;R. Chellali;R. Schlesiger;Ye Meng;D. Baither;G. Schmitz
中科院分区：
文献类型：
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作者：
Lei Zheng;R. Chellali;R. Schlesiger;Ye Meng;D. Baither;G. Schmitz
通过拉伸试验获得了Ni（Bi）合金热处理后的等时和等温塑性曲线，以表征该合金的脆化行为。等时塑性和等温塑性都有明显的极小值。扫描电子显微镜观察到的断口显示沿晶断裂的低塑性样品。通过聚焦离子束和透射电子显微镜观察，发现显微组织中没有晶粒内和晶界处的沉淀物。原子探针分析表明Bi有向晶界偏聚的强烈趋势。通过这些结果，讨论了现有的解释是不充分的，这两种脆化的机制是相同的，即热致非平衡晶界偏聚的Bi。
Isochronal and isothermal plasticity after thermal pre-treatments are obtained by tensile tests to characterize the embrittling behaviors of Ni(Bi) alloy. Both isochronal and isothermal plasticity show evident minima. Fractography observed by scanning electron microscopy displays intergranular fracture for samples of low plasticity. The microstructure is found to be free of precipitates within grains and at grain boundaries by focused ion beam and transmission electron microscopy. Atom probe analysis indicates a strong tendency of Bi segregation to grain boundaries. By these results, the existing interpretations are discussed to be inadequate and both embrittlement are confirmed to be identical in mechanism, i.e. thermo-induced non-equilibrium grain-boundary segregation of Bi.