Assessment of Hydrogen Embrittlement Susceptibility and Mechanism(s)in Quench and Tempered AISI 4135 Steel Using A Novel Fast Fracture Test in Bending  

作　　者：Tuhin Das Salim V.Brahimi Jun Song Stephen Yue 

机构地区：[1]Department of Materials Engineering,McGill University,Montreal,QC H3A OC5,Canada [2]Industrial Fasteners Institute,Cleveland,OH 44131,USA

出　　处：《Acta Metallurgica Sinica(English Letters)》2023年第7期1078-1094,共17页金属学报（英文版）

基　　金：This work was financially supported by the Government of Canada through Natural Sciences and Engineering Research Council(NSERC),and the industrial collaborators led by Industrial Fasteners Institute(USA),Canadian Fasteners Institute(CFI),Boeing Company(USA),Infasco(Canada)and the Research Council on Structural Connections(RCSC).

摘　　要：A newly proposed rapid fracture test in four-point bending was used to evaluate the effect of tempering on the hydrogen embrittlement(HE)susceptibility of an AISI 4135 steel,where it was tempered to four different strength(or hardness)levels.It was observed that HE susceptibility increases with the increase in hardness.It was shown that there will be minimal impact of hydrogen(H)on the fracture of materials with hardness 37 HRC and below,even if they are completely saturated with H.On the other hand,H will have similar detrimental effect on fracture properties of quench and tempered(Q and T)steels having hardness higher than 45 HRC.Ductile to brittle transition behavior was observed for a critical hardness(or strength)range as well as for a critical concentration level of H.Additionally,a critical H concentration was observed to exist for each of the strength levels.Fractography was performed in addition to microstructural characterization using transmission electron microscopy(TEM).A very good correlation was observed between the fast fracture test results and fractography.The fast fracture test was further compared with a conventional incremental step load(ISL)test for the evaluation of HE susceptibility.The ISL test results and fracture surface characteristics corroborate very well with the observations from the fast fracture test.This study successfully establishes the fast fracture test as a novel technique to study HE susceptibility and mechanism(s).

关 键 词：Hydrogen embrittlement(HE) Mechanical testing Fracture mechanics Martensitic steel HARDNESS Dislocation density 

分 类 号：TG111.91[金属学及工艺—物理冶金]