TRIP-Matrix-Composite Guest-edited by Horst Biermann

Transcription

1 The cover features Bending, a photograph by Detlev Müller, and depicts a square-shell honeycomb with 64 pores per inch from the work of Dr.-Ing. Christian Weigelt. Special Issue: TRIP-Matrix-Composite Guest-edited by Horst Biermann Editorial Editorial Adv. Eng. Mater. 2013, 15, 541 Communication Study of Reinforcing Mechanisms in TRIP-Matrix Composites under Compressive Loading by Means of Micromechanical Simulations S. Prüger,* L. Mehlhorn, U. Mühlich, M. Kuna Adv. Eng. Mater. 2013, 15, Particle reinforced TRIP-matrix composites, consisting of partially stabilized zirconia particles embedded in a TRIPsteel matrix, show a very heterogeneous phase transformation behavior. It is due to both the stress concentration and the void formation as a result of interface decohesion. The figure depicts the distribution of martensite volume fraction in the matrix and the volume fraction of monoclinic zirconia in the particle after uniaxial compression e = ADVANCED ENGINEERING MATERIALS 2013,15, No. 7 ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 535

2 The fatigue behavior of particle reinforced MMCs with high-alloyed CrMnNi steels as matrix reinforced with partially stabilized zirconia (Mg-PSZ) is investigated. It is shown, that the fatigue behavior is influenced significantly by the chemical composition of the steel matrix and Mg-PSZ volume fraction. Depending on the chemical composition, the high-alloyed steels show the TWIP and TRIP effect under cyclic loading. Influence of Matrix Strength and Volume Fraction of Mg-PSZ on the Cyclic Deformation Behavior of Hot Pressed TRIP/TWIP- Matrix Composite Materials A. Glage,* C. Weigelt, J. Räthel, Adv. Eng. Mater. 2013, 15, The effect of the manganese content (0 11%) on the transformation temperatures, the mechanical properties, and microstructure development of five highly alloyed 14Cr XMn 6Ni cast stainless steels with 0.1% nitrogen is studied. The temperature dependence of tensile properties in alloys is explained on the basis of varying contributions to the strength and ductility of deformation-induced martensite and twin formation mechanisms. Effect of Manganese on Microstructure and Mechanical Properties of Cast High Alloyed CrMnNi-N Steels M. Wendler,* A. Weiß, L. Krüger, J. Mola, A. Franke, A. Kovalev, S. Wolf Adv. Eng. Mater. 2013, 15, Electron beam welding of high alloy CrMnNi cast steels showing the TRIP and/or TWIP effect proved to be advantageous because of its short time energy input, which results in minimized thermal loading of the base material. Crack and pore-free welding seams with depths up to 26 mm were produced. EBSD investigations showed that the deformation mechanisms in the welding seam are qualitatively the same as in the base material. Electron Beam Welding of High Alloy CrMnNi Cast Steels with TRIP/TWIP Effect A. Buchwalder,* K. Rüthrich, R. Zenker, Adv. Eng. Mater. 2013, 15, Microstructure defects and their interactions contributing to the high energy absorption in highly alloyed austenitic CrMnNi TRIP steels: dislocations, stacking faults, Lomer-Cottrell locks, stacking fault tetrahedra, dislocation clusters; the e-martensite, twinned austenite and the a 0 -martensite, caused by the fluctuation of the stacking fault density and the lattice shearing within deformation bands, are analyzed using REM and TEM/ HRTEM. Microstructure Defects Contributing to the Energy Absorption in CrMnNi TRIP Steels D. Borisova,* V. Klemm,* S. Martin, S. Wolf, D. Rafaja Adv. Eng. Mater. 2013, 15, ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ADVANCED ENGINEERING MATERIALS 2013,15, No. 7

3 The Thermophysical Properties of Liquid TRIP/ TWIP-Steel Alloys Using the Maximum Bubble Pressure Method T. Dubberstein,* H.-P. Heller Adv. Eng. Mater. 2013, 15, The surface tension of copper, AISI 304 and the Cr-Mn-Ni steels are determined via the maximum bubble pressure method using zirconia capillary tubes. Oxygen adsorption in Cr-Ni steel decreases surface tension. Manganese is responsible for a decrease of surface tension values in Cr-Mn-Ni alloys. For Cr-Ni and Cr-Mn-Ni stainless steels temperature coefficient of surface tension changed to positive. Mg-PSZ Reinforced TRIP-Steel MMCs In Situ CT Investigations of Cruciform Samples under Compressive Loading U. Ballaschk,* H. Berek, D. Ehinger, C. G. Aneziris, L. Krüger Adv. Eng. Mater. 2013, 15, Mechanical in situ investigations on cruciform members of square-celled TRIP-steel/Mg-PSZ honeycomb structures are presented under uniform compressive load in a computer tomograph (XCT). The mechanical and structural characteristics of the cell wall node elements are compared to the damage mechanisms of the complete honeycomb specimens. Phase transformations in the Mg-PSZ particles are determined by EBSD. Microstructure Changes in TRIP Steel/Mg-PSZ Composites Induced by Low Compressive Deformation S. Martin,* S. Decker, L. Krüger, U. Martin, D. Rafaja Adv. Eng. Mater. 2013, 15, Strength and work hardening of TRIP matrix composite materials depend strongly on the testing temperature. Due to a temperature dependent driving force for the a 0 -martensite formation and a changing stacking fault energy in the metastable austenitic matrix, completely different deformation mechanisms can be observed at room temperature and at 1008C. With the transition from the formation of intrinsic stacking faults at 208C to extrinsic stacking faults at elevated temperatures, the TRIP effect is substituted by mechanical twinning. The stress induced martensitic transformation in the reinforcing zirconia particles increases the stress level of the MMC further. ADVANCED ENGINEERING MATERIALS 2013,15, No. 7 ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 537

4 The microstructure evolution during deformation and the mechanical behavior of an austenitic Cr Mn Ni as cast steel are investigated at various temperatures. The deformation-induced twinning and e/a -martensite formation the TWIP and TRIP effects occur in the investigate steel depending on the deformation temperature. For characterization and illustration of the TRIP/TWIP effects the STT and DTT diagrams are developed. Finally, the a -martensite nucleation threshold is determined, and an equation is proposed to describe the volume fraction of strain-induced a -martensite as a function of the total driving force. Thermodynamic-Mechanical Modeling of Strain-Induced a 0 -Martensite Formation in Austenitic Cr Mn Ni As-Cast Steel A. Kovalev,* M. Wendler, A. Jahn, A. Weiß, Adv. Eng. Mater. 2013, 15, The ZrO 2 MgO phase diagram is experimentally studied using XRD, SEM-EDX, and DTA. The ZrO 2 -based solutions are modeled as ionic solutions using compound energy formalism. The thermodynamic parameters are optimized using own and literature experimental data. The calculated ZrO 2 MgO phase diagram is used to interpret the microstructure and phase transformations observed in the industrial Mg-PSZ material in as-received and heat treated states. Experimental Investigation and Thermodynamic Modeling of the ZrO 2 MgO System D. Pavlyuchkov,* G. Savinykh, O. Fabrichnaya Adv. Eng. Mater. 2013, 15, The phase composition and the orientation relationship of several crystallites at the PSZ/TRIP steel interface before and after a mechanical deformation are studied in thin films and in a bulk composite sample using HRTEM, EDX and EELS. The analysis of the zirconium N 2,3 edge in the electron energy loss spectra allows to distinguish the cubic, tetragonal and monoclinic ZrO 2 phases from each other. Interface Phenomena Responsible for Bonding between TRIP Steel and Partially Stabilised Zirconia as Revealed by TEM A. Poklad,* M. Motylenko,* V. Klemm, G. Schreiber, S. Martin, S. Decker, B. Abendroth, M. Haverkamp, D. Rafaja Adv. Eng. Mater. 2013, 15, ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ADVANCED ENGINEERING MATERIALS 2013,15, No. 7

5 A Material Model of Particle Size Dependent Transformation Plasticity of PSZ Ceramics under Thermomechanical Loading In this article a material model of transformation plasticity in PSZ materials is presented. It features a crystallite size dependent phase transition criterion and nonlinear strain-temperature behaviour with hysteresis. L. Mehlhorn, U. Mühlich,* M. Kuna Adv. Eng. Mater. 2013, 15, Full paper Temperature Effects on the Deformation Behavior of High-Density TRIP Steel and Particle-Reinforced TRIP Steel/Zirconia Honeycombs Under Quasi-Static Compressive Loading D. Ehinger,* L. Krüger, U. Martin, C. Weigelt, C. G. Aneziris Adv. Eng. Mater. 2013, 15, This study is focused on the effects of material strengthening and reinforcing mechanisms on the crush resistance, deformability, and energy absorption capability of square-celled TRIP steel and TRIP steel/zirconia composite honeycomb structures under quasi-static out-of-plane compressive loading over a wide range of test temperatures. The microstructure and phase evolution in the cell wall material is investigated by magnetic force balance and EBSD measurements considering different deformation stages. ADVANCED ENGINEERING MATERIALS 2013,15, No. 7 ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 539