Review on the design of high-strength and hydrogen-embrittlement-resistant steels

Given the carbon peak and carbon neutrality era,there is an urgent need to develop high-strength steel with remarkable hydrogen embrittlement resistance.This is crucial in enhancing toughness and ensuring the utilization of hydrogen in emerging iron and steel materials.Simultaneously,the pursuit of enhanced metallic materials presents a cross-disciplinary scientific and engineering challenge.Developing high-strength,toughened steel with both enhanced strength and hydrogen embrittlement(HE)resistance holds significant theoretical and practical implications.This ensures secure hydrogen utilization and further carbon neutrality objectives within the iron and steel sector.Based on the design principles of high-strength steel HE resistance,this review provides a comprehensive overview of research on designing surface HE resistance and employing nanosized precipitates as intragranular hydrogen traps.It also proposes feasible recommendations and prospects for designing high-strength steel with enhanced HE resistance.

Minimally invasive method to treat a rare wrist injury with simultaneous fractures of the scaphoid and hook of hamate: A case report and literature review

Concomitant fractures of the hook of hamate and scaphoid are rare injuries to the wrist. Whenever these fractures cannot be effectively managed, nonunion or osteonecrosis is encountered. Subsequent treatment is thus much more challenging for a hand surgeon or orthopedist. Minimally invasive percutaneous internal fixation is an optimal treatment with the potential to minimize injury and reduce fractures. However, the control of iatrogenic injuries, including possible damage to the adjacent vital tissue, is a challenge that needs to be addressed. Herein,we describe the case of a 26-year-old man who presented with fractures to the scaphoid and hook of hamate in his left wrist. Minimally invasive treatment-with closed reduction and percutaneous fixation of the scaphoid, wrist arthroscopy, and closed reduction and percutaneous fixation of the hook of hamate-was performed at our institution. The Mayo score of the wrist, visual analog scale(VAS) for pain, grip strength, pinch strength, and wrist motion in radial/ulnar and flexion/extension deviation were recorded. Primary healing was achieved in both fractures. At the final follow-up, the Mayo score of the wrist was 100(excellent), the VAS score was 0(no pain),and the grip and pinch strength of his injured hand were 90.9% and 83.3%, respectively, compared with the contralateral hand(grip strength: left, 50 kg;right, 55 kg. Pinch strength: left, 20 kg;right, 24 kg). The radialulnar, flexion-extension, and forearm pronation-supination directions were 30°, 140°, and 90°, respectively.Minimally invasive closed reduction with percutaneous internal fixation is an optimal technique with satisfactory outcomes for simultaneous fractures of the hook of hamate and scaphoid. Provided in this paper are details of the technique and technical suggestions for performing the procedure.

Interactions between Pre-strain and Dislocation Structures and Its Effect on the Hydrogen Trapping Behaviors

This work investigated the effect of pre-strain and microstructures and their interactions on hydrogen trapping behaviors in case of 1-GPa high-strength martensitic steel Fe-0.05C-0.30Si-1.10Mn-3.50Ni-0.53Cr-0.50Mo-0.03 V(wt%).We found that the trapped reversible and trapped irreversible hydrogen contents increased significantly after applying a pre-strain of 5%,with an increase in the trapped reversible hydrogen content from 0.6 ppm in the original sample to 2.1 ppm.The hydrogen desorption activation energy also showed a slight increase.The microstructural evolution revealed that the concomitant dislocation cell-twin duplex microstructure with high-density tangled dislocations after pre-strain substantially increased the trapped reversible hydrogen contents.Additionally,the tangled dislocations pinned by the nanoprecipitates acted as deep irreversible hydrogen traps,increasing the trapped hydrogen at high temperatures after applying 5%pre-strain.These findings provide an expanded understanding of the hydrogen trapping behaviors of pre-strained microstructures.

Microstructure evolution of in-situ nanoparticles and its comprehensive effect on high strength steel

A novel steel strengthened by nanoparticles was investigated in this study. A Fe-based high-strength steel was developed by the trace-element regional supply method during deoxidization to generate in situ nanoparticles with a high number density in the matrix. The results show that the endogenous nanoparticles are aluminum oxide (AI2O3) and titanium oxide (Ti3O5) formed in the liquid melt. Al2O3 functioned as a heterogeneous nucleation site for MnS during solidification;the size of the resultant complex inclusions was approximately 1-2 jjim. Furthermore, 13 nm Nb(C,N) precipitates grew with the Ti30 5 during the tempering process. These in situ nanopartides strongly affected refining of the grain and inclusions. The investigated steel was strengthened more than 200 MPa by precipitation strengthening and more than 265 MPa by grain refinement strengthening according to the Ashby-Orowan mechanism and the Hall-Petch relationship, respectively.