Abstract The influence of advanced thermal insulation on energy consumption and temperature distribution during electric field assisted sintering of conductive stainless steel powder and non-conductive zirconia powder was investigated. Four types of tool setup were considered: i) without insulation, ii) with die wall insulation, iii) with additional insulation of die faces and iv) with spacers manufactured from carbon fiber reinforced carbon composite (CFRC). The influence of thermal insulation ...
Abstract In this work, a Fe-23Mn-1.5Al-0.3C twinning-induced plasticity steel was subjected to both symmetric (SR) and asymmetric rolling (ASR) to investigate the influence of an additional shear strain component introduced during asymmetric rolling on the microstructure and texture evolution as well as on the mechanical properties. ASR was performed using a roll diameter ratio of 2:1. Electron backscatter diffraction, transmission electron microscopy, and X-ray diffraction were utilized for car...
#1Marco Wendler(Freiberg University of Mining and Technology)H-Index: 10
#2C. Ullrich(Freiberg University of Mining and Technology)H-Index: 12
Last. Javad Mola(Freiberg University of Mining and Technology)H-Index: 11
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Abstract A novel quenching and partitioning (Q&P) processing was applied to the steel Fe-15Cr-3Ni-3Mn-0.5Si-0.12N-0.16C (wt.-%) with an almost fully austenitic microstructure in the solution annealed condition. The Q&P processing consisted of a subzero cooling step and a partitioning step at 450 °C. The fraction of α ′-martensite after the Q&P processing was nearly 58 vol%. During partitioning, M3C precipitates with an average size of 20 nm formed inside the α ′-martensite. Concurrently, the int...
Abstract A composite consisting of a TRIP (Transformation Induced Plasticity) steel matrix with 5 vol.% Mg-PSZ particles (MgO partially stabilized zirconia) as reinforcement and processed by Spark Plasma Sintering (SPS) was tested under compressive load at a strain rate of 200 s − 1 at both − 40 °C and room temperature. Due to the Mg-PSZ reinforcement, the very fine-grained steel and the low temperature, the material exhibited high strength (true compressive strength of 740 MPa at 1% nominal eng...
Abstract The aim of the present study was to combine the beneficial influences of both Twinning-Induced Plasticity (TWIP) and Transformation-Induced Plasticity (TRIP) effects on the mechanical properties and to adjust the contribution of both effects by suitable thermo-mechanical processing. Two high-manganese TRIP/TWIP steels were studied. In order to correlate the influence of the microstructural features to the mechanical properties, four specific conditions were set, i.e. pre-deformed, rever...
Abstract A novel high-strength steel has been made through thermo-mechanical controlled processing with the finish rolling temperature of 750 °C followed by air cooling. Subsequently, both partial austenitisation at 800 °C and fully austenitisation at 930 °C have been attempted for equal duration of 30 min prior to one step quenching and partitioning (Q&P) at 345 °C below M S temperature (365 °C). As-rolled steel reveals ferrite-bainite-martensite microstructures with a good combination of stren...
#1Michael Hauser(Freiberg University of Mining and Technology)H-Index: 6
#2Marco Wendler(Freiberg University of Mining and Technology)H-Index: 10
Last. Javad Mola(Freiberg University of Mining and Technology)H-Index: 11
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Abstract The deformation-induced formation of α′ martensite was investigated by tensile testing of a Fe-19Cr-3Mn-4Ni-0.15C-0.17N cast austenitic steel between −196 °C and 400 °C. The steel did not exhibit spontaneous α′ martensite formation at temperatures as low as −196 °C. Therefore, the critical driving force for the formation of α′ (−2780 J/mol) was obtained by determining the complementary mechanical energy necessary to trigger the deformation-induced α′ martensite at 0 °C. Driving forces f...
#2Cemal Cem Tasan(MIT: Massachusetts Institute of Technology)H-Index: 37
Last. Dierk Raabe(MPG: Max Planck Society)H-Index: 134
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Abstract Introduction of interlath reverted austenite is an effective method to design ductile lath martensitic steels. The challenge in this concept is that all reverted austenite films have similar mechanical stability, hence, they all undergo transformation-induced plasticity (TRIP) at the same strain level. Here we propose a new thermo-mechanical treatment route to activate the TRIP effect over a broad strain regime and refer to it as ‘spectral TRIP effect’. It aims at spreading the micro-me...
#1Qiuliang Huang(Freiberg University of Mining and Technology)H-Index: 5
#2Bruno C. De Cooman(POSTECH: Pohang University of Science and Technology)H-Index: 44
Last. Javad Mola(Freiberg University of Mining and Technology)H-Index: 11
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The influence of martensite fraction (f α′) on the stabilization of austenite was studied by quench interruption below M s temperature of an Fe-13Cr-0.31C (mass pct) stainless steel. The interval between the quench interruption temperature and the secondary martensite start temperature, denoted as θ, was used to quantify the extent of austenite stabilization. In experiments with and without a reheating step subsequent to quench interruption, the variation of θ with f α′ showed a transition after...
#2D.T. Pierce(Colorado School of Mines)H-Index: 10
Last. Amy J. Clarke(LANL: Los Alamos National Laboratory)H-Index: 23
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The effect of partitioning parameters on mechanical properties and carbon partitioning in quenching and partitioning (Q&P)-treated C-1.5Mn-1.5Si steels was studied using 0.3 wt.% and 0.4 wt.% carbon compositions. Fully austenitized specimens were quenched to a fixed quenching temperature followed by partitioning at 400°C and 450°C for varying times. In most cases, increasing the partitioning temperature decreased UTS and increased TE, and both UTS and TE decreased with increasing partitioning ti...
Last. Majid Vaseghi(Shahid Beheshti University)H-Index: 7
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In this research, hypereutectoid Si–Mn TRIP steel was prepared via casting method followed by thermomechanical processing and different heat treatments. Subsequently, fracture behavior and mechanical properties of the prepared steel were investigated. The time–temperature–transformation curves of the specimens were predicted by a simulation software. Their mechanical properties were studied through tensile, hardness, and impact tests. The microstructure and fracture behavior of the specimens wer...
#1Caroline Quitzke(Freiberg University of Mining and Technology)
Abstract In this study, the influence of various nitrogen contents (0.12-0.23 wt.%) on the mechanical properties, especially the strain-induced α´-martensite formation behavior, of the austenitic stainless steel X3CrMnNiMoN17-8-4 was investigated by temperature dependent in situ tensile tests. With the aid of in situ magnetic measurements during tensile test, the correlation between the strain-induced α´-martensite formation and the inflection points in the true stress-strain curve could be veri...
#1Sabine Decker(Freiberg University of Mining and Technology)H-Index: 10
#2Markus Radajewski(Freiberg University of Mining and Technology)H-Index: 8
Last. Lutz Krüger(Freiberg University of Mining and Technology)H-Index: 22
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This chapter analyses options to synthesis TRIP matrix composites (reinforced with Mg-PSZ), which stand out due to a high strength and the possibility to undergo a stress- and strain-induced phase transformation. These composites are processed using Field Assisted Sintering Technology (FAST). Both, the influence of the powder treatment before sintering and the impact of parameter setting during sintering by FAST are discussed. Due to a careful alignment of these factors, a TRIP matrix composite ...
The generation of a nickel-reduced, stainless spring steel strip with a thickness of 0.2 mm, producible under industrial conditions, is the aim of a transfer project together with the Institute of Metal Forming/TU BAF and the Auerhammer Metallwerk GmbH within the DFG Collaborative Research Centre (CRC) 799. The spring steel strip should exhibit a tensile strength of ≥1700 MPa in work-hardened and partitioned state. The mechanical and corrosive properties of the steel strip should be equal or bet...
