Research

15 pages, 19140 KiB

Open AccessArticle

Contact Geometry Modification of Friction-Welded Semi-Finished Products to Improve the Bonding of Hybrid Components

by Bernd-Arno Behrens, Johanna Uhe, Tom Petersen, Florian Nürnberger, Christoph Kahra, Ingo Ross and René Laeger

Metals 2021, 11(1), 115; https://doi.org/10.3390/met11010115 - 08 Jan 2021

Cited by 5 | Viewed by 1884

Abstract

To improve the bond strength of hybrid components when joined by friction welding, specimens with various front end surface geometries were evaluated. Rods made of aluminum AA6082 (AlSi1MgMn/EN AW-6082) and the case-hardening steel 20MnCr5 (AISI 5120) with adapted joining surface geometries were investigated [...] Read more.

To improve the bond strength of hybrid components when joined by friction welding, specimens with various front end surface geometries were evaluated. Rods made of aluminum AA6082 (AlSi1MgMn/EN AW-6082) and the case-hardening steel 20MnCr5 (AISI 5120) with adapted joining surface geometries were investigated to create both a form-locked and material-bonded joint. Eight different geometries were selected and tested. Subsequently, the joined components were metallographically examined to analyze the bonding and the resulting microstructures. The mechanical properties were tested by means of tensile tests and hardness measurements. Three geometrical variants with different locking types were identified as the most promising for further processing in a forming process chain due to the observed material bond and tensile strengths above 220 MPa. The hardness tests revealed an increase in the steel’s hardness and a softening of the aluminum near the transition area. Apparent intermetallic phases in the joining zone were analyzed by scanning electron microscopy (SEM) and an accumulation of silicon in the joining zone was detected by energy-dispersive X-ray spectroscopy (EDS). Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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9 pages, 2770 KiB

Open AccessArticle

Structural Characteristics of Multilayered Ni-Ti Nanocomposite Fabricated by High Speed High Pressure Torsion (HSHPT)

by Gheorghe Gurau, Carmela Gurau, Francisco Manuel Braz Fernandes, Petrica Alexandru, Vedamanickam Sampath, Mihaela Marin and Bogdan Mihai Galbinasu

Metals 2020, 10(12), 1629; https://doi.org/10.3390/met10121629 - 04 Dec 2020

Cited by 7 | Viewed by 1602

Abstract

It is generally accepted that severe plastic deformation (SPD) has the ability to produce ultrafinegrained (UFG) and nanocrystalline materials in bulk. Recent developments in high pressure torsion (HPT) processes have led to the production of bimetallic composites using copper, aluminum or magnesium alloys. [...] Read more.

It is generally accepted that severe plastic deformation (SPD) has the ability to produce ultrafinegrained (UFG) and nanocrystalline materials in bulk. Recent developments in high pressure torsion (HPT) processes have led to the production of bimetallic composites using copper, aluminum or magnesium alloys. This article outlines a new approach to fabricate multilayered Ni-Ti nanocomposites by a patented SPD technique, namely, high speed high pressure torsion (HSHPT). The multilayered composite discs consist of Ni-Ti alloys of different composition: a shape memory alloy (SMA) Ti-rich, whose Mf > RT, and an SMA Ni-rich, whose Af < RT. The composites were designed to have 2 to 32 layers of both alloys. The layers were arranged in different sequences to improve the shape recovery on both heating and cooling of nickel-titanium alloys. The manufacturing process of Ni-Ti multilayers is explained in this work. The evolution of the microstructure was traced using optical, scanning electron and transmission electron microscopes. The effectiveness of the bonding of the multilayered composites was investigated. The shape memory characteristics and the martensitic transition of the nickel-titanium nanocomposites were studied by differential scanning calorimetry (DSC). This method opens up new possibilities for designing various layered metal-matrix composites achieving the best combination of shape memory, deformability and tensile strength. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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22 pages, 3064 KiB

Open AccessArticle

Computer-Aided Engineering Environment for Designing Tailored Forming Components

by Tim Brockmöller, Renan Siqueira, Paul C. Gembarski, Iryna Mozgova and Roland Lachmayer

Metals 2020, 10(12), 1589; https://doi.org/10.3390/met10121589 - 27 Nov 2020

Cited by 12 | Viewed by 2595

Abstract

The use of multi-material forming components makes it possible to produce components adapted to the respective requirements, which have advantages over mono-material components. The necessary consideration of an additional material increases the possible degrees of freedom in product and manufacturing process development. As [...] Read more.

The use of multi-material forming components makes it possible to produce components adapted to the respective requirements, which have advantages over mono-material components. The necessary consideration of an additional material increases the possible degrees of freedom in product and manufacturing process development. As a result, development becomes more complex and special expert knowledge is required. To counteract this, computer-aided engineering environments with knowledge-based tools are increasingly used. This article describes a computer-aided engineering environment (CAEE) that can be used to design hybrid forming components that are produced by tailored forming, a process chain developed in the Collaborative Research Center (CRC) 1153. The CAEE consists of a knowledge base, in which the knowledge necessary for the design of tailored forming parts, including manufacturer restrictions, is stored and made available. For the generation of rough and detailed design and for elaboration the following methods are used. The topology optimization method, Interfacial Zone Evolutionary Optimization (IZEO), which determines the material distribution. The design of optimized joining zone geometries, by robust design. The elaboration of the components by means of highly flexible computer-aided design (CAD) models, which are built according to the generative parametric design approach (GPDA). Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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16 pages, 5241 KiB

Open AccessArticle

Characterization and Modeling of Intermetallic Phase Formation during the Joining of Aluminum and Steel in Analogy to Co-Extrusion

by Bernd-Arno Behrens, Hans Jürgen Maier, Christian Klose, Hendrik Wester, Susanne Elisabeth Thürer, Norman Heimes and Johanna Uhe

Metals 2020, 10(12), 1582; https://doi.org/10.3390/met10121582 - 26 Nov 2020

Cited by 4 | Viewed by 1801

Abstract

The reinforcement of light metal components with steel allows to increase the strength of the part while keeping the weight comparatively low. Lateral angular co-extrusion (LACE) offers the possibility to produce hybrid coaxial profiles consisting of steel and aluminum. In the present study, [...] Read more.

The reinforcement of light metal components with steel allows to increase the strength of the part while keeping the weight comparatively low. Lateral angular co-extrusion (LACE) offers the possibility to produce hybrid coaxial profiles consisting of steel and aluminum. In the present study, the effect of the process parameters temperature, contact pressure and time on the metallurgical bonding process and the development of intermetallic phases was investigated. Therefore, an analogy experiment was developed to reproduce the process conditions during co-extrusion using a forming dilatometer. Based on scanning electron microscopy analysis of the specimens, the intermetallic phase seam thickness was measured to calculate the resulting diffusion coefficients. Nanoindentation and energy dispersive X-ray spectroscopy measurements were carried out to determine the element distribution and estimate properties within the joining zone. The proposed numerical model for the calculation of the resulting intermetallic phase seam width was implemented into a finite element (FE) software using a user-subroutine and validated by experimental results. Using the subroutine, a numerical prediction of the resulting intermetallic phase thicknesses is possible during the tool design, which can be exploited to avoid the weakening of the component strength due to formation of wide intermetallic phase seams. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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14 pages, 5256 KiB

Open AccessArticle

Microstructural Evolution and Mechanical Properties of Hybrid Bevel Gears Manufactured by Tailored Forming

by Bernd-Arno Behrens, Anna Chugreeva, Julian Diefenbach, Christoph Kahra, Sebastian Herbst, Florian Nürnberger and Hans Jürgen Maier

Metals 2020, 10(10), 1365; https://doi.org/10.3390/met10101365 - 13 Oct 2020

Cited by 6 | Viewed by 2285

Abstract

The production of multi-metal bulk components requires suitable manufacturing technologies. On the example of hybrid bevel gears featuring two different steels at the outer surface and on the inside, the applicability of the novel manufacturing technology of Tailored Forming was investigated. In a [...] Read more.

The production of multi-metal bulk components requires suitable manufacturing technologies. On the example of hybrid bevel gears featuring two different steels at the outer surface and on the inside, the applicability of the novel manufacturing technology of Tailored Forming was investigated. In a first processing step, a semi-finished compound was manufactured by cladding a substrate using a plasma transferred arc welding or a laser hotwire process. The resulting semi-finished workpieces with a metallurgical bond were subsequently near-net shape forged to bevel gears. Using the residual heat after the forging process, a process-integrated heat treatment was carried out directly after forming. For the investigations, the material combinations of 41Cr4 with C22.8 (AISI 5140/AISI 1022M) and X45CrSi9-3 with C22.8 (AISI HNV3/AISI 1022M) were applied. To reveal the influence of the single processing steps on the resulting interface, metallographic examinations, hardness measurements and micro tensile tests were carried out after cladding, forging and process-integrated heat treatment. Due to forging and heat-treatment, recrystallization and grain refinement at the interface and an increase in both, hardness and tensile strength, were observed. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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19 pages, 15779 KiB

Open AccessArticle

Investigations on Tailored Forming of AISI 52100 as Rolling Bearing Raceway

by Timm Coors, Maximilian Mildebrath, Christoph Büdenbender, Felix Saure, Mohamad Yusuf Faqiri, Christoph Kahra, Vannila Prasanthan, Anna Chugreeva, Tim Matthias, Laura Budde, Florian Pape, Florian Nürnberger, Thomas Hassel, Jörg Hermsdorf, Ludger Overmeyer, Bernd Breidenstein, Berend Denkena, Bernd-Arno Behrens, Hans Jürgen Maier and Gerhard Poll

Metals 2020, 10(10), 1363; https://doi.org/10.3390/met10101363 - 13 Oct 2020

Cited by 11 | Viewed by 2421

Abstract

Hybrid cylindrical roller thrust bearing washers of type 81212 were manufactured by tailored forming. An AISI 1022M base material, featuring a sufficient strength for structural loads, was cladded with the bearing steel AISI 52100 by plasma transferred arc welding (PTA). Though AISI 52100 [...] Read more.

Hybrid cylindrical roller thrust bearing washers of type 81212 were manufactured by tailored forming. An AISI 1022M base material, featuring a sufficient strength for structural loads, was cladded with the bearing steel AISI 52100 by plasma transferred arc welding (PTA). Though AISI 52100 is generally regarded as non-weldable, it could be applied as a cladding material by adjusting PTA parameters. The cladded parts were investigated after each individual process step and subsequently tested under rolling contact load. Welding defects that could not be completely eliminated by the subsequent hot forming were characterized by means of scanning acoustic microscopy and micrographs. Below the surface, pores with a typical size of ten µm were found to a depth of about 0.45 mm. In the material transition zone and between individual weld seams, larger voids were observed. Grinding of the surface after heat treatment caused compressive residual stresses near the surface with a relatively small depth. Fatigue tests were carried out on an FE8 test rig. Eighty-two percent of the calculated rating life for conventional bearings was achieved. A high failure slope of the Weibull regression was determined. A relationship between the weld defects and the fatigue behavior is likely. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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17 pages, 10459 KiB

Open AccessArticle

by Bernd Breidenstein, Berend Denkena, Alexander Krödel, Vannila Prasanthan, Gerhard Poll, Florian Pape and Timm Coors

Metals 2020, 10(10), 1339; https://doi.org/10.3390/met10101339 - 07 Oct 2020

Cited by 5 | Viewed by 1858

Abstract

By combining different materials, for example, high-strength steel and unalloyed structural steel, hybrid components with specifically adapted properties to a certain application can be realized. The mechanical processing, required for production, influences the subsurface properties, which have a deep impact on the lifespan [...] Read more.

By combining different materials, for example, high-strength steel and unalloyed structural steel, hybrid components with specifically adapted properties to a certain application can be realized. The mechanical processing, required for production, influences the subsurface properties, which have a deep impact on the lifespan of solid components. However, the influence of machining-induced subsurface properties on the operating behavior of hybrid components with a material transition in axial direction has not been investigated. Therefore, friction-welded hybrid shafts were machined with different process parameters for hard-turning and subsequent deep rolling. After machining, subsurface properties such as residual stresses, microstructures, and hardness of the machined components were analyzed. Significant influencing parameters on surface and subsurface properties identified in analogy experiments are the cutting-edge microgeometry,

\bar{S}

, and the feed, f, during turning. The deep-rolling overlap, u, hardly changes the residual stress depth profile, but it influences the surface roughness strongly. Experimental tests to determine fatigue life under combined rolling and rotating bending stress were carried out. Residual stresses of up to −1000 MPa, at a depth of 200 µm, increased the durability regarding rolling-contact fatigue by 22%, compared to the hard-turned samples. The material transition was not critical for failure. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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23 pages, 20756 KiB

Open AccessArticle

Numerical Simulation and Experimental Validation of the Cladding Material Distribution of Hybrid Semi-Finished Products Produced by Deposition Welding and Cross-Wedge Rolling

by Jens Kruse, Maximilian Mildebrath, Laura Budde, Timm Coors, Mohamad Yusuf Faqiri, Alexander Barroi, Malte Stonis, Thomas Hassel, Florian Pape, Marius Lammers, Jörg Hermsdorf, Stefan Kaierle, Ludger Overmeyer and Gerhard Poll

Metals 2020, 10(10), 1336; https://doi.org/10.3390/met10101336 - 06 Oct 2020

Cited by 9 | Viewed by 2887

Abstract

The service life of rolling contacts is dependent on many factors. The choice of materials in particular has a major influence on when, for example, a ball bearing may fail. Within an exemplary process chain for the production of hybrid high-performance components through [...] Read more.

The service life of rolling contacts is dependent on many factors. The choice of materials in particular has a major influence on when, for example, a ball bearing may fail. Within an exemplary process chain for the production of hybrid high-performance components through tailored forming, hybrid solid components made of at least two different steel alloys are investigated. The aim is to create parts that have improved properties compared to monolithic parts of the same geometry. In order to achieve this, several materials are joined prior to a forming operation. In this work, hybrid shafts created by either plasma (PTA) or laser metal deposition (LMD-W) welding are formed via cross-wedge rolling (CWR) to investigate the resulting thickness of the material deposited in the area of the bearing seat. Additionally, finite element analysis (FEA) simulations of the CWR process are compared with experimental CWR results to validate the coating thickness estimation done via simulation. This allows for more accurate predictions of the cladding material geometry after CWR, and the desired welding seam geometry can be selected by calculating the cladding thickness via CWR simulation. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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Graphical abstract

16 pages, 6386 KiB

Open AccessArticle

Applying Membrane Mode Enhanced Cohesive Zone Elements on Tailored Forming Components

by Felix Töller, Stefan Löhnert and Peter Wriggers

Metals 2020, 10(10), 1333; https://doi.org/10.3390/met10101333 - 05 Oct 2020

Cited by 2 | Viewed by 1467

Abstract

Forming of hybrid bulk metal components might include severe membrane mode deformation of the joining zone. This effect is not reflected by common Traction Separation Laws used within Cohesive Zone Elements that are usually applied for the simulation of joining zones. Thus, they [...] Read more.

Forming of hybrid bulk metal components might include severe membrane mode deformation of the joining zone. This effect is not reflected by common Traction Separation Laws used within Cohesive Zone Elements that are usually applied for the simulation of joining zones. Thus, they cannot capture possible damage of the joining zone under these conditions. Membrane Mode Enhanced Cohesive Zone Elements fix this deficiency. This novel approach can be implemented in finite elements. It can be used within commercial codes where an implementation as a material model is beneficial as this simplifies model preparation with the existing GUIs. In this contribution, the implementation of Membrane Mode Enhanced Cohesive Zone Elements as a material model is presented within MSC Marc along with simulations showing the capabilities of this approach. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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12 pages, 9820 KiB

Open AccessArticle

Influence of Ultrasound on Pore and Crack Formation in Laser Beam Welding of Nickel-Base Alloy Round Bars

by Jan Grajczak, Christian Nowroth, Sarah Nothdurft, Jörg Hermsdorf, Jens Twiefel, Jörg Wallaschek and Stefan Kaierle

Metals 2020, 10(10), 1299; https://doi.org/10.3390/met10101299 - 29 Sep 2020

Cited by 7 | Viewed by 2055

Abstract

Welding by laser beam is a method for creating deep and narrow welds with low influence on the surrounding material. Nevertheless, the microstructure and mechanical properties change, and highly alloyed materials are prone to segregation. A new promising approach for minimizing segregation and [...] Read more.

Welding by laser beam is a method for creating deep and narrow welds with low influence on the surrounding material. Nevertheless, the microstructure and mechanical properties change, and highly alloyed materials are prone to segregation. A new promising approach for minimizing segregation and its effects like hot cracks is introducing ultrasonic excitation into the specimen. The following investigations are about the effects of different ultrasonic amplitudes (2/4/6 µm) and different positions of the weld pool in the resonant vibration distribution (antinode, centered, and node position) for bead on plate welds on 2.4856 nickel alloy round bars (30 mm diameter) with a laser beam power of 6 kW. The weld is evaluated by visual inspection and metallographic cross sections. The experiments reveal specific mechanisms of interaction between melt and different positions regarding to the vibration shape, which influence weld shape, microstructure, segregation, cracks and pores. Welding with ultrasonic excitation in antinode position improves the welding results. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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15 pages, 5494 KiB

Open AccessFeature PaperArticle

Lateral Angular Co-Extrusion: Geometrical and Mechanical Properties of Compound Profiles

by Susanne Elisabeth Thürer, Julius Peddinghaus, Norman Heimes, Ferdi Caner Bayram, Burak Bal, Johanna Uhe, Bernd-Arno Behrens, Hans Jürgen Maier and Christian Klose

Metals 2020, 10(9), 1162; https://doi.org/10.3390/met10091162 - 28 Aug 2020

Cited by 12 | Viewed by 2970

Abstract

A novel co-extrusion process for the production of coaxially reinforced hollow profiles has been developed. Using this process, hybrid hollow profiles made of the aluminum alloy EN AW-6082 and the case-hardening steel 20MnCr5 (AISI 5120) were produced, which can be forged into hybrid [...] Read more.

A novel co-extrusion process for the production of coaxially reinforced hollow profiles has been developed. Using this process, hybrid hollow profiles made of the aluminum alloy EN AW-6082 and the case-hardening steel 20MnCr5 (AISI 5120) were produced, which can be forged into hybrid bearing bushings by subsequent die forging. For the purpose of co-extrusion, a modular tooling concept was developed where steel tubes made of 20MnCr5 are fed laterally into the tool. This LACE (lateral angular co-extrusion) process allows for a variation of the volume fraction of the reinforcement by using steel tubes with different wall thicknesses, which enabled the production of compound profiles having reinforcement contents of either 14 vol.% or 34 vol.%. The shear strength of the bonding area of these samples was determined in push-out tests. Additionally, mechanical testing of segments of the hybrid profiles using shear compression tests was employed to provide information about the influence of different bonding mechanisms on the strength of the composite zone. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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12 pages, 5050 KiB

Open AccessArticle

Feeling Machine for Process Monitoring of Turning Hybrid Solid Components

by Berend Denkena, Benjamin Bergmann and Matthias Witt

Metals 2020, 10(7), 930; https://doi.org/10.3390/met10070930 - 10 Jul 2020

Cited by 5 | Viewed by 2455

Abstract

The realization of the increasing automation of production systems requires the guarantee of process security as well as the resulting workpiece quality. For this purpose, monitoring systems are used, which monitor the machining based on machine control signals and external sensors. These systems [...] Read more.

The realization of the increasing automation of production systems requires the guarantee of process security as well as the resulting workpiece quality. For this purpose, monitoring systems are used, which monitor the machining based on machine control signals and external sensors. These systems are challenged by innovative design concepts such as hybrid components made of different materials, which lead to new disturbance variables in the process. Therefore, it is important to obtain as much process information as possible in order to achieve a robust and sensitive evaluation of the machining. Feeling machines with force sensing capabilities represent a promising approach to assist the monitoring. This paper provides, for the first time, an overview of the suitability of the feeling machine for process monitoring during turning operations. The process faults tool breakage, tool wear, and the variation of the material transition position of hybrid shafts that were researched and compared with a force dynamometer. For the investigation, longitudinal turning processes with shafts made of EN AW-6082 and 20MnCr5 were carried out. The results show the feeling machine is sensitive to all kinds of examined errors and can compete with a force dynamometer, especially for roughing operations. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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15 pages, 20700 KiB

Open AccessArticle

Design, Setup, and Evaluation of a Compensation System for the Light Deflection Effect Occurring When Measuring Wrought-Hot Objects Using Optical Triangulation Methods

by Lorenz Quentin, Carl Reinke, Rüdiger Beermann, Markus Kästner and Eduard Reithmeier

Metals 2020, 10(7), 908; https://doi.org/10.3390/met10070908 - 07 Jul 2020

Cited by 5 | Viewed by 1879

Abstract

In this paper, we present a system to compensate for the light deflection effect during the optical geometry measurement of a wrought-hot object. The acquired 3D data can be used to analyze the formed geometry of a component directly after a hot forging [...] Read more.

In this paper, we present a system to compensate for the light deflection effect during the optical geometry measurement of a wrought-hot object. The acquired 3D data can be used to analyze the formed geometry of a component directly after a hot forging process without waiting for the needed cooling time to room temperature. This may be used to parameterize the process and to detect defect components early in the production process, among others. The light deflection as the deviation from the linear path of the light is caused by an inhomogeneous refractive index field surrounding the hot object. We present the design and setup for a nozzle-based forced air flow actuator, which suppresses the light deflection effect. The design process includes a simulation of the developing field, as well as of the interaction of the field with an external forced air flow. The cooling effect of the air flow is evaluated, and conclusions are drawn from the conflicting interests of good measurement conditions against the forced cooling of the hot object. The findings are then implemented in the physical setup of the suppression system. The system is evaluated using a previously established method based on optical triangulation and fringe projection. Other occurring effects and their influence on the evaluation are considered and discussed. Full article

(This article belongs to the Special Issue Hybrid Bulk Metal Components)

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