scholarly journals Design of an Effective Heat Treatment Involving Intercritical Hardening for High Strength/High Elongation of 0.2C–3Al–(6–8.5)Mn–Fe TRIP Steels: Microstructural Evolution and Deformation Behavior

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1275 ◽  
Author(s):  
Yanjie Mou ◽  
Zhichao Li ◽  
Xiaoteng Zhang ◽  
Devesh Misra ◽  
Lianfang He ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stress Relaxation ◽  
Deformation Behavior ◽  
High Strength ◽  
Total Elongation ◽  
Trip Effect ◽  
High Ductility ◽  
Trip Steels ◽  
Effective Heat ◽  
High Elongation

High strength/high elongation continues to be the primary challenge and focus for medium-Mn steels. It is elucidated herein via critical experimental analysis that the cumulative contribution of transformation-induced plasticity (TRIP) and microstructural constituents governs high strength/high elongation in 0.2C–3Al–(6–8.5)Mn–Fe steels. This was enabled by an effective heat treatment involving a combination of intercritical hardening and tempering to obtain high strength/high ductility. An excellent combination of high ultimate tensile strength of 935–1112 MPa and total elongation of 35–40% was obtained when the steels were subjected to intercritical hardening in the temperature range of 700–750 °C and low tempering at 200 °C. The intercritical hardening impacted the coexistence of austenite, ferrite, and martensite, such that the deformation behavior varied with the Mn content. The excellent obtained properties of the steels are attributed to the cumulative contribution of the enhanced TRIP effect of austenite and the microstructural constituents, ferrite and martensite. The discontinuous TRIP effect during deformation involved stress relaxation, which was responsible for the high ductility. Lamellar austenite, unlike the equiaxed microstructure, is envisaged to induce stress relaxation during martensitic transformation, resulting in the discontinuous TRIP effect.

Heat Treatment of the New High-Strength High-Ductility Al-Mg-Si-Mn Alloys with Sc, Zr and Cr Additions

2020 ◽  
Author(s):  
O. Trudonoshyn ◽  
O. Prach ◽  
P. Randelzhofer ◽  
K. Durst ◽  
С. Körner
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
High Ductility

scholarly journals Enhanced aging kinetics in Al-Mg-Si alloys by up-quenching

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Florian Schmid ◽  
Philip Dumitraschkewitz ◽  
Thomas Kremmer ◽  
Peter J. Uggowitzer ◽  
Ramona Tosone ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Cluster Formation ◽  
High Strength ◽  
Second Phase ◽  
Second Phase Particles ◽  
Negative Effect ◽  
High Elongation ◽  
Aging Kinetics ◽  
Complex Parts

AbstractPrecipitation-hardened aluminium alloys typically obtain their strength by forming second-phase particles, which, however, often have a negative effect on formability. To enable both lightweight construction and forming of complex parts such as body panels, high strength and formability are required simultaneously. Cluster hardening is a promising approach to achieve this. Here, we show that short thermal spikes, denoted as up-quenching, increase aging kinetics, which we attribute to the repeated process of vacancies being formed at high temperatures and retained when cooled to lower temperatures. Combined with further heat treatment, the up-quenching process promotes rapid and extensive cluster formation in Al-Mg-Si alloys, which in turn generates significant strengthening at industrially relevant heat treatment time scales. The high elongation values also observed are attributed to reduced solute depleted zones along grain boundaries.

Cold Spray Deposition of Heat-Treated Inconel 718 Powders

2021 ◽  
Author(s):  
Lorena Perez ◽  
Jake Colburn ◽  
Luke N. Brewer ◽  
Michael Renfro ◽  
Tim McKechnie
Keyword(s):  
Heat Treatment ◽  
Cold Spray ◽  
Inconel 718 ◽  
Deformation Behavior ◽  
Spray Deposition ◽  
High Strength ◽  
Particle Deformation ◽  
Delta Phase ◽  
High Particle ◽  
Heat Treated

Abstract In this work; Inconel 718 gas-atomized powder was successfully heat treated over the range of 700-900°C. As-atomized and as-heat treated powders were cold sprayed with both nitrogen and helium gasses. Cold spray of high strength materials is still challenging due to their resistance to particle deformation affecting the resulting deposit properties. Powder heat treatment to modify its deformation behavior has recently been developed for aluminum alloy powders; however; there is no literature reported for Inconel 718 powders. The microstructural evolution of the powder induced by the heat treatment was studied and correlated with their deformation behavior during the cold spray deposition. Deposits sprayed with heat-treated powders at 800 and 900 °C and nitrogen showed less particle deformation and higher porosity as compare to as-atomized deposit associated to the presence of delta phase in the powders precipitated by the heat treatment. In contrast; deposits sprayed with helium using both powder conditions; as-atomized and as heat-treated powders; showed high particle deformation and low porosity indicating that the type of gas has a greater effect on the particle deformation than the delta phase precipitated in the heat-treated powders. These results contribute to understanding the role of powder microstructure evolution induced by heat treatment on the cold spray deposits properties.

Heat treatment of the new high-strength high-ductility Al–Mg–Si–Mn alloys with Sc, Zr and Cr additions

Materialia ◽  
2021 ◽  
Vol 15 ◽  
pp. 100981
Author(s):  
O. Trudonoshyn ◽  
O. Prach ◽  
P. Randelzhofer ◽  
K. Durst ◽  
С. Körner
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
High Ductility

scholarly journals High Versatility of Niobium Alloyed AHSS

2017 ◽  
Vol 62 (3) ◽  
pp. 1485-1491 ◽  
Author(s):  
L. Kučerová ◽  
K. Opatová ◽  
J. Káňa ◽  
H. Jirková
Keyword(s):  
Heat Treatment ◽  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength ◽  
Processing Parameters ◽  
High Ductility ◽  
Processing Strategies ◽  
Cooling Schedules ◽  
Final Microstructure ◽  
Steel Processing

AbstractThe effect of processing parameters on the final microstructure and properties of advanced high strength CMnSiNb steel was investigated. Several processing strategies with various numbers of deformation steps and various cooling schedules were carried out, namely heat treatment without deformation, conventional quenching and TRIP steel processing with bainitic hold or continuous cooling. Obtained multiphase microstructures consisted of the mixture of ferrite, bainite, retained austenite and M-A constituent. They possessed ultimate tensile strength in the range of 780-970 MPa with high ductility A5mmabove 30%. Volume fraction of retained austenite was for all the samples around 13%. The only exception was reference quenched sample with the highest strength 1186 MPa, lowest ductility A5mm= 20% and only 4% of retained austenite.

The Analysis of SPD Paradox by Computer Modeling Technique

2009 ◽  
Vol 633-634 ◽  
pp. 231-248
Author(s):  
Igor V. Alexandrov ◽  
Roza G. Chembarisova
Keyword(s):  
Plastic Deformation ◽  
Thermal Treatment ◽  
Deformation Behavior ◽  
High Strength ◽  
High Ductility ◽  
Angular Pressing ◽  
Deformation Twins ◽  
Ultrafine Grained ◽  
Favorable Conditions ◽  
Dislocation Density Increase

The paper has viewed the manifestation of the paradox of severe plastic deformation (SPD), caused by the occurrence of preexisting deformation twins in ultrafine-grained Cu, which has been obtained by the combination of the SPD method, accomplished by an equal-channel angular pressing with the conventional methods of deformation-thermal treatment. The high strength of the obtained samples has proved to be conditioned by the occurrence of the high density of the coherent twin boundaries, serving as effective obstacles on the way of slipping dislocations. Moreover, the occurrence of the twins creates favorable conditions for the dislocation density increase both in the grains with the twins and in the grains without them. As a result the sample hardens, contributing additionally into its strength. Simultaneously it manifests high ductility. By doing so the deformation behavior of the sample is mainly conditioned by the grain boundaries of grains free from the twins. The results were obtained on the basis of the dislocation-based model which develops models of Y. Estrin and L. Tóth, M. Zehetbauer, and L. Remy.

Low-Carbon Manganese TRIP Steels

2007 ◽  
Vol 539-543 ◽  
pp. 4327-4332 ◽  
Author(s):  
M.J. Merwin
Keyword(s):  
Manganese Content ◽  
High Strength ◽  
Total Elongation ◽  
Hot Strip Mill ◽  
Low Carbon ◽  
Trip Steels ◽  
Batch Annealing ◽  
Rolled Condition ◽  
Conventional Manner ◽  
Hot Rolled

The development of TRansformation Induced Plasicity (TRIP) steels has seen much activity in recent years, due to the promise of very high formability combined with high strength. The accepted method for production of as-hot-rolled TRIP steel employs multistage runout table cooling and coiling in the bainitic transformation temperature regime. As an alternative to confronting the production difficulties the accepted strategy presents, a program was begun to evaluate the potential of 0.1C-6.0Mn steels processed in a more conventional manner. Three laboratory heats were melted to consider the effect of manganese content on processing and properties. The steels were found to be fully hardenable with conventional hot-strip mill processing and subsequent batch annealing simulations produced significant retained austenite levels. The combination of the prior martensitic microstructure in the as-hot-rolled condition, and austenite created during annealing, resulted in remarkable combinations of strength and ductility. In the as-hot-rolled condition, tensile strengths exceeding 1400 MPa were observed, with total elongations of approximately 10 percent. Optimum properties were found when samples were annealed at approximately 650°C. While this treatment reduced the tensile strength to 800-1000 MPa, the total elongation increased to between 30 percent and 40 percent. UTS*TE products exceeding 30,000 MPa-% were observed, making these materials attractive for high strength, high ductility applications.

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