scholarly journals Recent Progress in Understanding the Nano/Micro-Mechanical Behavior of Austenite in Advanced High Strength Steels

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1927
Author(s):  
Qingwen Guan ◽  
Wenjun Lu ◽  
Binbin He
Keyword(s):  
Mechanical Behavior ◽  
High Performance ◽  
Recent Progress ◽  
Low Cost ◽  
High Strength Steels ◽  
High Strength ◽  
Small Scale ◽  
Advanced High Strength Steels ◽  
Dislocation Plasticity ◽  
Austenite Grains

Advanced high strength steels (AHSS) are developed to reduce vehicle weight without sacrificing passenger safety. The newly developed AHSS frequently incorporates the austenite as the intrinsic component with large amount and good stability, which is realized by carefully designed alloying elements and thermo-mechanical processing. To explore the great potential of austenite in enhancing the strain hardening behavior of AHSS, detailed information on the mechanical behavior of single austenite grain is a prerequisite, which can be collected by a small-scale test. The present work reviews the recent progress in understanding the nano/micro-mechanical behavior of austenite in varied AHSS. Three different plasticity modes including dislocation plasticity, martensitic transformation, and deformation twinning can be observed in the austenite grains during small-scale tests, given proper stacking fault energy and crystal orientation. The remaining issues concerned with the nano/micro-mechanical behavior of austenite are discussed. The present review advances the general understanding of the nano/micro-mechanical behavior of austenite grains in AHSS, which may shed light on the precise austenite engineering with the development of new AHSS, realizing the dream of high-performance steels at low cost.

Third generation of advanced high-strength steels: Processing routes and properties

2016 ◽  
Vol 233 (2) ◽  
pp. 209-238 ◽  
Author(s):  
Tarun Nanda ◽  
Vishal Singh ◽  
Virender Singh ◽  
Arnab Chakraborty ◽  
Sandeep Sharma
Keyword(s):  
Automobile Industry ◽  
Second Generation ◽  
Low Cost ◽  
High Strength Steels ◽  
High Strength ◽  
Cost Effective ◽  
Processing Route ◽  
Third Generation ◽  
Specific Strength ◽  
Advanced High Strength Steels

The automobile industry is presently focusing on processing of advanced steels with superior strength–ductility combination and lesser weight as compared to conventional high-strength steels. Advanced high-strength steels are a new class of materials to meet the need of high specific strength while maintaining the high formability required for processing, and that too at reasonably low cost. First and second generation of advanced high-strength steels suffered from some limitations. First generation had high strength but low formability while second generation possessed both strength and ductility but was not cost effective. Amongst the different types of advanced high-strength steels grades, dual-phase steels, transformation-induced plasticity steels, and complex phase steels are considered as very good options for being extended into third generation advanced high-strength steels. The present review presents the various processing routes for these grades developed and discussed by different authors. A novel processing route known as quenching and partitioning route is also discussed. The review also discusses the resulting microstructures and mechanical properties achieved under various processing conditions. Finally, the key findings with regards to further research required for the processing of advanced high-strength steels of third generation have been discussed.

scholarly journals Enhancing the Mechanical Properties of a Hot Rolled High-Strength Steel Produced by Ultra-Fast Cooling and Q&P Process

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 958 ◽  
Author(s):  
Teng Wu ◽  
Run Wu ◽  
Bin Liu ◽  
Wen Liang ◽  
Deqing Ke
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Controlled Rolling ◽  
Grain Structure ◽  
Ultra Fast Cooling ◽  
Advanced High Strength Steels ◽  
Fast Cooling ◽  
Austenite Grains ◽  
Hot Rolled

The quenching and partitioning (Q&P) process of advanced high strength steels results in a significant enhancement in their strength and ductility. The development of controlled rolling and cooling technology provides an efficient tool for microstructural design in steels. This approach allows to control phase transformations in order to generate the desired microstructure in steel and, thus, to achieve the required properties. To refine grain structure in a Fe-Si-Mn-Nb steel and to generate the microstructure consisting of martensitic matrix with embedded retained austenite grains, hot rolling and pressing combined with ultrafast cooling and Q&P process is employed. The slender martensite in hot rolled Q&P steel improves the strength of test steel and the flake retained austenite improves the plasticity and work hardening ability through the Transformation Induced Plasticity (TRIP) effect.

scholarly journals Cyclic Deformation of Advanced High-Strength Steels: Mechanical Behavior and Microstructural Analysis

2009 ◽  
Vol 40 (2) ◽  
pp. 342-353 ◽  
Author(s):  
Timothy B. Hilditch ◽  
Ilana B. Timokhina ◽  
Leigh T. Robertson ◽  
Elena V. Pereloma ◽  
Peter D. Hodgson
Keyword(s):  
Mechanical Behavior ◽  
Cyclic Deformation ◽  
Microstructural Analysis ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels

Pulsed LASER-(Micro)TIG Welding of Automotive Dissimilar Zn-Coated Advanced High Strength Steels Thin Sheets in Overlap Configuration

2016 ◽  
Vol 1138 ◽  
pp. 147-152
Author(s):  
Aurel Valentin Bîrdeanu
Keyword(s):  
High Performance ◽  
Pulsed Laser ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Industrial Applications ◽  
Cost Ratio ◽  
Hybrid Welding ◽  
Thin Sheets ◽  
Advanced High Strength Steels

The development and implementation into a high number of industrial applications of materials categorized as (Advanced) High Strength Steels (AHSS) due to their high performance per cost ratio is more and more present and this trend is also combined with the development and implementation of new joining technologies and processes, including laser-arc hybrid processes.The paper presents the results of applying Pulsed LASER-(micro)TIG hybrid welding process, for realizing overlap joints for Zn-coated (A)HSS materials in dissimilar configurations, joints that were presented as designed based on UltraLight Steel Auto Body (ULSAB) principles.The influence of main hybrid welding process parameters was investigated in order to establish if one can obtain joints with high values for the shear strength resistance for some of the actually used dissimilar steel combinations based on designs applied throughout ULSAB project and the autos built following these principles.

Finite Element Simulation of Chain-Die Forming U Profiles with Variable Cross-Section

2017 ◽  
Vol 898 ◽  
pp. 1177-1182 ◽  
Author(s):  
Y.G. Li ◽  
Y. Sun ◽  
H.L. Huang ◽  
D.Y. Li ◽  
S.C. Ding
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Low Cost ◽  
High Strength Steels ◽  
High Strength ◽  
Variable Cross Section ◽  
Roll Forming ◽  
Variable Cross ◽  
Advanced High Strength Steels ◽  
Die Forming

Roll forming has been widely used to manufacture constant cross-section products because of high quality, efficiency and low cost. It is quite epidemic in producing automobile parts made of advanced high strength steels (AHSS) nowadays. However, with the development of the vehicle industry and diversity of the products, variable cross-section profiles have attracted more and more attention. The traditional roll forming technique is difficult to meet the requirements. Chain-die forming which was introduced in recent years makes it possible. Chain-die forming is an extension of roll forming and its key characteristic is enlarging the rotation radii of the moulds, by which the deformation zone is extended. The study focused on the finite element simulations of Chain-die forming U profiles with variable cross-section, including variable width and height. The feasibility of Chain-die forming producing variable cross-section products was verified by the perfect simulation results. The advantage of Chain-die forming was that there was no need to design the intermediate moulds except the finished-profile ones, which reduced the mould quantity immensely. Then the cost was lower.

scholarly journals Current Challenges and Opportunities in Microstructure-Related Properties of Advanced High-Strength Steels

2020 ◽  
Vol 51 (11) ◽  
pp. 5517-5586 ◽  
Author(s):  
Dierk Raabe ◽  
Binhan Sun ◽  
Alisson Kwiatkowski Da Silva ◽  
Baptiste Gault ◽  
Hung-Wei Yen ◽  
...  
Keyword(s):  
Recent Progress ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced Characterization ◽  
Critical Discussion ◽  
Press Hardening ◽  
Advanced High Strength Steels ◽  
Bainitic Steels ◽  
Challenges And Opportunities ◽  
Recent Developments

Abstract This is a viewpoint paper on recent progress in the understanding of the microstructure–property relations of advanced high-strength steels (AHSS). These alloys constitute a class of high-strength, formable steels that are designed mainly as sheet products for the transportation sector. AHSS have often very complex and hierarchical microstructures consisting of ferrite, austenite, bainite, or martensite matrix or of duplex or even multiphase mixtures of these constituents, sometimes enriched with precipitates. This complexity makes it challenging to establish reliable and mechanism-based microstructure–property relationships. A number of excellent studies already exist about the different types of AHSS (such as dual-phase steels, complex phase steels, transformation-induced plasticity steels, twinning-induced plasticity steels, bainitic steels, quenching and partitioning steels, press hardening steels, etc.) and several overviews appeared in which their engineering features related to mechanical properties and forming were discussed. This article reviews recent progress in the understanding of microstructures and alloy design in this field, placing particular attention on the deformation and strain hardening mechanisms of Mn-containing steels that utilize complex dislocation substructures, nanoscale precipitation patterns, deformation-driven transformation, and twinning effects. Recent developments on microalloyed nanoprecipitation hardened and press hardening steels are also reviewed. Besides providing a critical discussion of their microstructures and properties, vital features such as their resistance to hydrogen embrittlement and damage formation are also evaluated. We also present latest progress in advanced characterization and modeling techniques applied to AHSS. Finally, emerging topics such as machine learning, through-process simulation, and additive manufacturing of AHSS are discussed. The aim of this viewpoint is to identify similarities in the deformation and damage mechanisms among these various types of advanced steels and to use these observations for their further development and maturation.

Tensile Strength of Single Electrospun Nanofibers

2011 ◽  
Vol 175-176 ◽  
pp. 294-298 ◽  
Author(s):  
Kai Wei ◽  
Jian Hua Xia ◽  
Naotaka Kimura ◽  
Taiki Nakamura ◽  
Zhi Juan Pan ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
High Performance ◽  
Spider Silk ◽  
Natural Fibers ◽  
Small Diameter ◽  
Weight Ratio ◽  
Electrospun Nanofibers ◽  
High Strength ◽  
Small Scale ◽  
Structure Property

Researchers have paid much attention to small-scale natural fibers among the biological materials to seek innovative methods in order to create new high performance materials. Recently, spider dragline silk fibers are being studied because of their unique combination of high strength to weight ratio and high extensibility, which leads to a tough and lightweight fiber. Biomimetic fibers based on spider silk have been a focus of research for the past decade. However, there are still many unanswered questions about the mechanisms by which silk achieves its unique mechanical properties, as well as challenges in mechanical testing of electrospinning silk nanofibers which are often hindered by both small diameters and limited material availability. A method to characterize local mechanical behavior in small diameter nanofibers was developed to both improve understanding of structure-property in natural fibers and provide a method for comparing mechanical behavior in natural and electrospinning fibers.

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