Interplay between alloying and tramp element effects on temper embrittlement in bcc iron: DFT and thermodynamic insights
arxiv(2024)
摘要
The details of the temper embrittlement mechanism in steels caused by
impurities are unknown. Especially from an atomistic point of view, there are
still open questions regarding their interactions with alloying elements such
as Ni, Cr, and Mo. Therefore, we used density functional theory to investigate
the segregation and co-segregation behavior and the resulting influence on the
cohesion of three representative tilt grain boundaries in iron. The results are
implemented in a multi-site and multi-component kinetic and thermodynamic model
for grain boundary segregation, to gain insights into the temporal and final
grain boundary coverage. Our results show that the segregation tendency of As,
Sb, and Sn is stronger than that of the alloying elements and significantly
mitigates the grain boundary cohesion. Depending on the GB type, interactions
between Sb and Sn vary from negligible to strongly attractive, which increases
the likelihood of co-segregation. The cohesion-weakening effect is further
amplified when elements such as Sb, Sn, and As co-segregate, compared to their
individual segregation. In contrast, the co-segregation of Ni and Cr does not
significantly increase the enrichment of impurities at grain boundaries, and
their impact on cohesion is found to be negligible. The ability of Mo to
mitigate reversible temper embrittlement is primarily attributed to its
cohesion-enhancing effect and its capability to repel tramp elements from GBs,
rather than scavenging them within the bulk, as suggested by previous
literature.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要