scholarly journals Development of 1.2 GPa Ferrite-based Lightweight Steels via Low-temperature Tempering

2021 ◽  
Vol 59 (10) ◽  
pp. 695-703
Author(s):  
Hyo Ju Bae ◽  
Kwang Kyu Ko ◽  
Hyoung Seok Park ◽  
Jae Seok Jeong ◽  
Jung Gi Kim ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ferrite Matrix ◽  
Total Elongation ◽  
Industrial Applications ◽  
Lower Strength ◽  
Size Dependent ◽  
Dislocation Movement ◽  
Austenite Grains ◽  
Scale Characterization ◽  
Increased Strength

Previously reported low-Mn ferritic-based lightweight steels are potential candidates for industrial applications, however, they typically exhibit lower strength, with < 1 GPa and lower strength-ductility balance, than medium- and high-Mn austenitic lightweight steels. Herein, we introduce a low-temperature tempering-induced partitioning (LTP) treatment that avoids the strength-ductility dilemma of low-Mn ferriticbased steels. When the LTP process was performed at 330 oC for 665 s, the strength of typical ferritic base Fe-2.8Mn5.7Al0.3C (wt%) steel with heterogeneously sized metastable austenite grains embedded in a ferrite matrix, exceeded 1.1 GPa. Notably, the increased strength-ductility balance of the LTP-processed ferritic steel was comparable to that of the high-Mn based austenitic lightweight steel series. Using microscale to nearatomic scale characterization we found that the simultaneous improvement in strength and total elongation could be attributed to size-dependent dislocation movement, and controlled deformation-induced martensitic transformation.

Application of the Continuous Rheoconversion Process (CRP) to Low Temperature HPDC-Part I: Microstructure

2006 ◽  
Vol 116-117 ◽  
pp. 402-405 ◽  
Author(s):  
Qin Yue Pan ◽  
Stuart Wiesner ◽  
Diran Apelian
Keyword(s):  
Low Temperature ◽  
Scale Up ◽  
Microstructural Characterization ◽  
Industrial Applications ◽  
Primary Phase ◽  
Heat Extraction ◽  
Initial Stage ◽  
Fraction Solid ◽  
Die Castings

The continuous rheoconversion process (CRP) is a novel slurry-on-demand process that was developed at MPI/WPI in 2002. The process is based on a passive liquid mixing technique in which the nucleation and growth of the primary phase are controlled using a specially designed “reactor”. The reactor provides heat extraction, copious nucleation, and forced convection during the initial stage of solidification, thus leading to the formation of globular structures. This paper presents our recent work on the scale-up of the CRP for industrial applications. Specifically, we demonstrate an important application of the CRP to low temperature (low fraction solid) HPDC. In Part I of this paper, we present salient results on microstructural characterization of CRP processed castings vs. conventional die castings.

scholarly journals Effects of Low-Temperature Tempering on Microstructure and Properties of the Laser-Cladded AISI 420 Martensitic Stainless Steel Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 451 ◽  
Author(s):  
Hongmei Zhu ◽  
Yongzuo Li ◽  
Baichun Li ◽  
Zhenyuan Zhang ◽  
Changjun Qiu
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Martensitic Stainless Steel ◽  
Testing Machine ◽  
Industrial Applications ◽  
Slight Reduction ◽  
Micro Hardness ◽  
Microstructure And Properties ◽  
Steel Coating ◽  
Aisi 420

Post-treatment is crucial to improve the comprehensive performance of laser-cladded martensitic stainless steel coatings. In this work, a low-temperature tempering treatment (210 °C), for the first time, was performed on the laser-cladded AISI 420 martensitic stainless steel coating. The microstructure and properties of the pre- and post-tempering specimens were carefully investigated by XRD, SEM, TEM, a micro-hardness tester, a universal material testing machine and an electrochemical workstation. The results show that the as-cladded AISI 420 stainless steel coating mainly consisted of martensite, austenite, Fe3C and M23C6 carbides. The phase constituent of the coating remained the same, however, the martensite decomposed into finer tempered martensite with the precipitation of numerous nano-sized Fe3C carbides and reverted austenite in the as-tempered specimen. Moreover, a slight reduction was found in the micro-hardness and tensile strength, while a significant increase in elongation was achieved after tempering. The fractography showed a transition from brittle fracture to ductile fracture accordingly. The as-tempered coating exhibited a striking combination of mechanical properties and corrosion resistance. This work can provide a potential strategy to enhance the overall properties of the laser-deposited Fe-based coating for industrial applications.

scholarly journals The size dependent strength of Fe, Nb and V micropillars at room and low temperature

Materialia ◽  
2019 ◽  
Vol 7 ◽  
pp. 100424 ◽  
Author(s):  
Halil Yilmaz ◽  
Craig J. Williams ◽  
Jared Risan ◽  
Brian Derby
Keyword(s):  
Low Temperature ◽  
Size Dependent

scholarly journals Strong Interactions between Austenite and the Matrix of Medium-Mn Steel during Intercritical Annealing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3366 ◽  
Author(s):  
Tianpeng Zhou ◽  
Cunyu Wang ◽  
Chang Wang ◽  
Wenquan Cao ◽  
Zejun Chen
Keyword(s):  
Grain Size ◽  
Annealing Temperature ◽  
Ferrite Matrix ◽  
Strong Interactions ◽  
Recrystallization Process ◽  
Austenite Grain Size ◽  
Recrystallization Kinetics ◽  
Average Grain Size ◽  
The Matrix ◽  
Austenite Grains

The effects of heat treatment on the microstructure evolution was studied in regards to austenite nucleation and grain growth. It was found that the austenite nucleation and matrix recrystallization kinetics of samples annealed at 675 °C for different times were revealed, implying a strong interaction between the ferrite matrix and austenite. The recrystallization of the matrix during annealing provided favorable conditions for austenite nucleation and growth, and the formation of austenite during this process reduced the matrix recrystallization kinetics, thus delaying the recrystallization process of the matrix around the austenite grains. The statistical results for the austenite grain size under different annealing temperatures indicated that the average grain size of the austenite slightly increases with increasing of the annealing temperature, but the austenite with the largest grain size grows faster at the same temperature. This difference is attributed to the strict Kurdjumov Sachs (KS) orientation relationship (OR) between the austenite grains and the matrix, because the growth of austenite with a strict KS OR with the matrix is often inhibited during annealing. In contrast, the austenite maintains a non-strict KS OR with the matrix and can grow preferentially with increasing annealing temperature and time.

Nano-alumina powders/ceramics derived from aluminum foil waste at low temperature for various industrial applications

2016 ◽  
Vol 183 ◽  
pp. 121-125 ◽  
Author(s):  
Ahmed A.M. El-Amir ◽  
Emad M.M. Ewais ◽  
Ahmed R. Abdel-Aziem ◽  
Adel Ahmed ◽  
Bahgat E.H. El-Anadouli
Keyword(s):  
Low Temperature ◽  
Aluminum Foil ◽  
Industrial Applications ◽  
Nano Alumina

scholarly journals Non-destructive characterization of superionic conductor: lithium nitride

2014 ◽  
Vol 32 (4) ◽  
pp. 626-632 ◽  
Author(s):  
Pramod Yadawa
Keyword(s):  
Low Temperature ◽  
Temperature Variation ◽  
Elastic Constants ◽  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Industrial Applications ◽  
Superionic Conductor ◽  
Lithium Nitride ◽  
Thermal And Electrical Properties ◽  
Non Destructive

AbstractHigher order elastic constants have been calculated in hexagonally structured superionic conductor Li3N at room temperature using the interaction potential model. The temperature variation of the ultrasonic velocities was evaluated along different angles with z axis (unique axis) of the crystal, using the second order elastic constants. The ultrasonic velocity decreased with the temperature along a particular orientation of the unique axis. Temperature variation of the thermal relaxation time and Debye average velocities was also calculated along the same orientation. The temperature dependency of ultrasonic properties was discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behavior of ultrasonic attenuation as a function of temperature and the cause responsible for attenuation is phonon-phonon interaction. The mechanical properties of Li3N at low temperature are better than at high temperature because at low temperature it has low ultrasonic attenuation. Superionic conductor lithium nitride has many industrial applications, such as those used in portable electronic devices.

The aqueous geochemistry of thallium: speciation and solubility of thallium in low temperature systems

2009 ◽  
Vol 6 (5) ◽  
pp. 441 ◽  
Author(s):  
Yongliang Xiong
Keyword(s):  
Low Temperature ◽  
Solubility Product ◽  
Formation Constants ◽  
Industrial Applications ◽  
Thermodynamic Database ◽  
Aqueous Geochemistry ◽  
The Earth ◽  
Soil Solutions ◽  
Wide Range ◽  
Cadmium And Lead

Environmental context. The aqueous geochemistry of thallium is not well known in comparison with cadmium and lead, although it is more highly toxic, and at the same time has a wide range of industrial applications. A database allowing us to reliably predict the speciation and solubility of thallium in various environments in low temperature systems would be invaluable in providing some understanding of thallium’s mobilisation and mitigation. We propose here such a thermodynamic database based on critical reviews. Abstract. Thallium is a highly toxic element, and at the same time it has a wide range of applications in industry. Therefore, it is important to know its speciation and solubility under low temperature conditions. This study expands the thermodynamic database of the first paper of this series on the aqueous geochemistry of thallium by providing the formation constants of some important thallium complexes, including TlEDTA3–, TlOx– (Ox: oxalate), TlSuc– (Suc: succinate), TlMal– (Mal: malonate) and TlHPO4–. This study also recommends the solubility product constant of TlCl(s) as 10–3.65. The combined database allows us to model reliably the speciation and solubility of thallium in the Earth surface environments. As an example, the speciation and solubility of thallium in soil solutions are presented based on thermodynamic calculations.

scholarly journals Interaction Between Edge Dislocation and Single-Layered Graphene in Aluminum Matrix Investigated by Molecular Dynamics Simulation

2022 ◽  
Vol 2152 (1) ◽  
pp. 012034
Author(s):  
Liu Chen ◽  
Zhencheng Li ◽  
Sai Xu ◽  
Aixue Sha
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Mechanical Response ◽  
Aluminum Matrix ◽  
Shear Plane ◽  
Computational Method ◽  
Dynamics Simulation ◽  
Size Dependent ◽  
Graphene Interface ◽  
Dislocation Movement

Abstract The influence of graphene on dislocation movement and subsequent mechanical response of aluminum is investigated by the computational method of molecular dynamics simulation. A Lennard–Jones potential describing Al-C interaction was obtained through ab initio calculation. It was observed that the 2D graphene could reinforce Al matrix similar to the traditional Orowan mechanism. The Al/graphene interface first attract the gliding dislocation to reduce the system energy, which is unlike the grain boundary to repel gliding dislocations through pile-up mechanism. With the increase of stress, dislocation attracted and trapped at the front of graphene could glide along the interface and finally bypass it through climbing when graphene is orientated out of the shear plane. In addition, the strengthening ability of graphene is size dependent, showing a linear relationship between strength increment and graphene size.

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