Effects of Al addition on deformation and fracture mechanisms in two high manganese TWIP steels

2011 ◽  
Vol 528 (6) ◽  
pp. 2922-2928 ◽  
Author(s):  
Kwang-Geun Chin ◽  
Chung-Yun Kang ◽  
Sang Yong Shin ◽  
Seokmin. Hong ◽  
Sunghak Lee ◽  
...  
Keyword(s):  
Fracture Mechanisms ◽  
High Manganese ◽  
Deformation And Fracture ◽  
Twip Steels ◽  
Al Addition

Fatigue Behavior of High Manganese TWIP Steels and of Low Alloy Q&P Steels for Car-Body Applications

2014 ◽  
Vol 783-786 ◽  
pp. 713-720
Author(s):  
Paolo Matteis ◽  
Giorgio Scavino ◽  
R. Sesana ◽  
F. D’Aiuto ◽  
Donato Firrao
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Austenitic Steels ◽  
Fracture Mechanisms ◽  
High Manganese ◽  
Cold Forming ◽  
Austenitic Structure ◽  
Plasticity Effect ◽  
Twip Steels

The automotive TWIP steels are high-Mn austenitic steels, with a relevant C content, which exhibit a promising combination of strength and toughness, arising from the ductile austenitic structure, which is strengthened by C, and from the TWIP (TWinning Induced Plasticity) effect. The microstructure of the low-alloy Q&P steels consists of martensite and austenite and is obtained by the Quenching and Partitioning (Q&P) heat treatment, which consists of: austenitizing; quenching to the Tqtemperature, comprised between Msand Mf; soaking at the Tppartitioning temperature (Tpbeing equal to or slightly higher than Tq) to allow carbon to diffuse from martensite to austenite; and quenching to room temperature. The fatigue behavior of these steels is examined both in the as-fabricated condition and after pre-straining and welding operations, which are representative of the cold forming and assembling operations performed to fabricate the car-bodies. Moreover, the microscopic fracture mechanisms are assessed by means of fractographic examinations.

scholarly journals The Role of Hydrogen on the Behavior of Intergranular Cracks in Bicrystalline α-Fe Nanowires

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 294
Author(s):  
Jiaqing Li ◽  
Cheng Lu ◽  
Long Wang ◽  
Linqing Pei ◽  
Ajit Godbole ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Nanocrystalline Materials ◽  
Fracture Mechanisms ◽  
Bulk Materials ◽  
Cleavage Process ◽  
Deformation And Fracture ◽  
Dynamics Simulations ◽  
Crack Trapping ◽  
Cleavage Failure

Hydrogen embrittlement (HE) has been extensively studied in bulk materials. However, little is known about the role of H on the plastic deformation and fracture mechanisms of nanoscale materials such as nanowires. In this study, molecular dynamics simulations are employed to study the influence of H segregation on the behavior of intergranular cracks in bicrystalline α-Fe nanowires. The results demonstrate that segregated H atoms have weak embrittling effects on the predicted ductile cracks along the GBs, but favor the cleavage process of intergranular cracks in the theoretically brittle directions. Furthermore, it is revealed that cyclic loading can promote the H accumulation into the GB region ahead of the crack tip and overcome crack trapping, thus inducing a ductile-to-brittle transformation. This information will deepen our understanding on the experimentally-observed H-assisted brittle cleavage failure and have implications for designing new nanocrystalline materials with high resistance to HE.

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