Synergistic effects of Nb and Mo on hydrogen-induced cracking of pipeline steels:A combined experimental and numerical study

作     者：Shiqi Zhang Luming Qi Shilong Liu Zhixian Peng Y.Frank Cheng Feng Huang Jing Liu Shiqi Zhang;Lumning Qi;Shilong Liu;Zhixian Peng;Y.Frank Cheng;Feng Huang;Jing Liu

作者机构：The State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan 430081China Institute of Advanced Steels and MaterialsSchool of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical EngineeringUniversity of CalgaryCalgaryAB T2N 1N4Canada Hubei Engineering Technology Research Centre of Marine Materials and Service SafetyWuhan University of Science and TechnologyWuhan 430081China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2023年第158卷第27期

页      面：156-170页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：the support from the Na-tional Natural Science Foundation of China(No.52101092,and 52231003) the Natural Science Foundation of Hubei Province of China(No.2021CFA023) the International Science and Technology Cooperation Project of Hubei Province(2021EHB006) the Young Elite Scientists Sponsorship Program by CAST(No.20210324) the Petro China Innovation Foundation(No.2020D-5007-0311)。 

主　　题：Hydrogen-induced cracking Nb-Mo microalloying Hydrogen permeation Precipitate Pipeline steel 

摘      要：The synergistic effects of Nb and Mo on hydrogen-induced cracking(HIC)of pipeline steels were studied experimentally and numerically.The results showed that Mo was primarily segregated at grain-boundaries(GBs)or solid-dissolved in the matrix,while most Nb and a small amount of Mo formed dis-persed(Nb,Mo)C nano-precipitates and refined the microstructure.Compared with Nb alloying,the multi-ple additions of Nb-Mo played dual roles in affecting H diffusion:primarily,the H-traps densities such as GBs,precipitates,and solute Mo atoms increased,providing an advantage;however,Mo slightly reduced the H-trapping capacity of precipitates,playing an adverse role.Nonetheless,the beneficial effects far outweighed the adverse effects,thereby reducing H diffusivity and inhibiting crack initiation.Addition-ally,Nb and Mo hindered crack propagation synergistically as follows:(i)Mo enhanced GB cohesion by repelling H,impeding intergranular cracking and hydrogen-enhanced decohesion(HEDE);(ii)Nb reduced the proportion of3/high-angle grain boundaries,increasing cracking resistance;(iii)(Nb,Mo)C precip-itates impeded H-dislocation interactions,reducing the hydrogen-enhanced localized plasticity(HELP).