报告题目： grain boundary segregation and its impact on phase transformation and hydrogen embrittlement in high-strength al alloys 高强铝合金晶界偏聚、析出及氢脆
报告人：赵欢博士 德国马普学会钢铁研究所博士后研究员
报告时间：2022年4月19日下午3点
报告地点：安徽工业大学秀山校区冶金楼南 302会议室 (线上)
报告对象：全校感兴趣的教师和学生
邀请人：黄贞益、夏文真
承办单位：安徽省低碳冶金与流程控制工程研究中心、冶金工程学院微纳组织与力学研究所
报告人简介：
dr. huan zhao is working at the max-planck-institut für eisenforschung (mpie, germany) as a postdoctoral researcher. she received her ph.d. degree at mpie and rwth aachen university in october 2019. dr. zhao was honored with the acta student award 2018 and the tms light metals subject award - aluminum alloys. dr. zhao is devoted to unveiling the microstructure-property relationship, hydrogen embrittlement, and corrosion in structural materials. she has published 26 articles in peer-reviewed journals such as nature, physical review letters, acta materialia, etc. in addition, dr. zhao also served as a guest editor for an international sci journal and reviewer for journals in physical metallurgy.
赵欢，博士毕业于德国马普钢铁研究所&德国亚琛工业大学，现为德国马普学会钢铁研究所博士后研究员。研究方向包括金属材料的设计、加工、微观组织、力学行为；金属氢脆与腐蚀等。相关成果在nature, physical review letters, acta materialia 等杂志发表 (26篇) 。曾获 tms light metal subject award, acta student award和 icaa early career researcher award. 担任一个国际sci期刊客座编辑和金属材料学术期刊的审稿人。
报告内容：
high-strength 7xxx al alloys are the primary material of choice for structural components of airplanes owing to their high strength-to-weight ratio. unfortunately, 7xxx al alloys are susceptible to hydrogen embrittlement and subject to intergranular fracture, which severely limits their lifetime. overcoming these intrinsic limitations requires gaining a precise understanding of the composition evolution of grain boundaries and their interactions with hydrogen. in this talk, the effect of solute segregation on the grain boundary phase transformation and faceting behavior will be shown. near-atomic-scale analysis of hydrogen associated with specific microstructural features by using cryo-transfer atom probe tomography will be presented. the critical role of grain boundary on the hydrogen-assisted embrittlement will be discussed through atomistic ab initio calculations, along with potential mitigation strategies for improving hydrogen embrittlement resistance.
参考文献：
1.h. zhao, p. chakraborty, d. ponge, t. hickel, b. sun, c-h. wu, b. gault, d. raabe, hydrogen trapping and embrittlement in high-strength al-alloys, nature, 602, 437-441, (2022).
2.h. zhao, l. huber, w. lu, n.j. peter, d.y. an, f. de geuser, g. dehm, d. ponge, j. neugebauer, b. gault, d. raabe, interplay of chemistry and faceting at grain boundaries in a model al alloy, physical review letters, 124, 106102, (2020).
3.h. zhao, f. de geuser, a. kwiatkowski da silva, a. szczepaniak, b. gault, d. ponge, d. raabe, segregation assisted grain boundary precipitation in a model al-zn-mg-cu alloy, acta materialia, 156, 318-329, (2018).
高强铝合金因其具有高强度质量比而被广泛应用在航空及宇航工业。然而高强铝合金在长期服役过程中，往往受环境影响而发生氢脆与晶间断裂等局部破坏从而严重威胁服役产品的安全。澄清晶界偏聚的微观机制和氢在材料中的分布对提高高强铝合金耐用性起着至关重要的作用。本报告将以7050为例，展开阐述晶界偏聚机理及晶界上化学成分和结构的交互作用，并基于冷冻三维原子探针表征，澄清第二相颗粒和晶界处的氢原子级分布。在此基础上运用密度泛函理论来阐明氢致晶间断裂的原由。研究结果有助于加深晶界偏聚与氢脆理论并进一步指导抗氢脆铝合金设计。
