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 

机构地区：[1]The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China [2]Institute of Advanced Steels and Materials,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [3]Department of Mechanical Engineering,University of Calgary,Calgary,AB T2N 1N4,Canada [4]Hubei Engineering Technology Research Centre of Marine Materials and Service Safety,Wuhan University of Science and Technology,Wuhan 430081,China

出　　处：《Journal of Materials Science & Technology》2023年第27期156-170,共15页材料科学技术（英文版）

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)。

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).

关 键 词：Hydrogen-induced cracking Nb-Mo microalloying Hydrogen permeation PRECIPITATE Pipeline steel 

分 类 号：TG146.23[一般工业技术—材料科学与工程]