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The material requirements for the frog of a turnout are quite complex. The crossing nose region of the frog represents a discontinuity in the track as the wheel needs to change from one rail to the other. This causes increased dynamic contact forces and slip between wheel and frog. The high contact pressures and slip can cause damage such as wear, rolling contact fatigue and severe plastic deformation in the frog. The material from which the frog is constructed plays a crucial role in the development of damage. On the one hand, a plastic material response can reduce the contact pressures by an adaption of the frog’s geometry. On the other hand, materials have a different resistance to wear, crack initiation and growth. To clarify the requirements for materials for the manufacture of frogs, five different steel grades used to create frogs that are in service in various railway turnouts were investigated. The chosen materials were ‘Hadfield steel’ (an Mn-13, abrasion-resistant grain-refined steel with 400 HV), bainitic railway steel, tempered steel 51CrV4 (DIN 1.8159) and maraging steel. They were investigated in the same conditions as they would experience in service, covering a variety of steel microstructures and macroscopic hardness values. To compare the materials’ responses to the high impact forces, their impact fracture toughness was measured and selected fracture surfaces were investigated with scanning electron microscopy. To compare their response to the cyclic loading, the materials were tested with respect to their monotonic tensile strength as well as fatigue strength by means of low cycle fatigue tests. Measurements of the fracture toughness KIC were performed on all materials to compare their fracture resistance. The achieved results can be used as input data for finite-element-based calculations of the local loading conditions in railway turnouts. Additionally, the comparison can help the choice of the best material for specific loading conditions, i.e. specific crossing geometries and track loading conditions.

The microstructure of the Cr/CrN and Ti/TiN multilayers coatings deposited with the pulsed laser deposition (PLD) technique was studied using transmission electron microscope Philips CM20 TWIN (200 kV). It was found that the metallic buffer layers are characterized by the smallest columnar crystallite size and the highest defect density; this might rise their hardness but compromise the coating adhesion. The intermediate metallic layers showed a larger and less defected columnar structure as compared with the nitride layers, what should improve the coatings toughness. The scratch test performed with a Rockwell penetrator of 200 μm diameter loaded from 0.03 N up to 20 N indicated that the switching from a single layer to a multilayered metal/nitride coating of the same thickness improved the resistance to scratch test in case of Ti/TiN from 16.4 N for a TiN single layered to 22.9 N for a 32 layered coating and Cr/CrN from 4.4 N for a CrN single layered to 6.6 for a 32 layered ones.

Fatigue due to thermal cycling is one of the main reasons for the damage of tools used in die casting processes. In order to investigate the thermal fatigue behaviour of tool steels a thermal fatigue testing facility was designed and built up. For better understanding of the mechanisms of thermal fatigue finite element-simulations were carried out. To specify the cyclic material behaviour push-pull-tests at different temperatures were performed. The Chaboche-model was used to describe the kinematic material response. Isotropic softening is also taken into account. Depending on the arising accumulated plastic strain stable cyclic deformation or continuous softening occurs. The results are consistent with the accomplished thermal fatigue tests on different hot work tool steels.

The aim of the present work was the improvement of titanium–aluminium nitride (TiAlN) coating by the solid-solution hardening with carbon atoms leading to titanium–aluminium carbonitride (Ti,Al)CxN1−x coatings with varying carbon (x) and nitrogen contents. The request of low deposition temperatures which are indispensable for the coating of heat-sensitive materials like tool steels of high hardness and polymers was reached by the application of the room temperature pulsed laser deposition (PLD) technique. A Nd:YAG laser of 1064 nm wavelength operated at two different laser pulse energies was used in the ablation experiments of pure TiAl targets (50 at.% Al) in various C2H2–N2 gas mixtures. The results reveal a strong dependency of the gas mixture on the C and N content of the coatings. Furthermore, the different pulse energies change the ratio of Ti/Al atoms in the grown coatings. The crystallization was influenced too by the pulse energy and, thus, the energy and distribution of the atoms, ions and clusters. For the hardness and elastic moduli, two distinct stages in dependency on the crystallinity were found: High carbon contents lead due to the formation of pure carbon precipitations, found in the Raman investigations, to the destruction of the crystallin structure and, thus, to up to 60% lower hardnesses and elastic moduli. A low friction behaviour was found for coatings of the higher Al contents deposited at lower laser pulse energies due to the formation of carbon rich transfer layers on both the coatings and the Al2O3 counterparts.

Titanium carbonitride (TiC x N 1− x ) hard coatings possess excellent tribological behavior in metal punching and forming as well as high biocompatibility. Because almost all PVD and CVD coating techniques for TiC x N 1− x coatings require substrate temperatures higher than 150–200 °C for reaching sufficient adhesion strength to the substrate surface, there is high demand in the development of large-area and high-rate low-temperature vacuum deposition processes. In the present work, this call was fulfilled by the application of the room temperature pulsed laser deposition (PLD) for TiC x N 1− x coating with various carbon ( x ) and nitrogen contents. A pulsed Nd:YAG laser (wavelength: 1064 nm) was used for the vaporization of pure titanium targets in low-pressure N 2 /C 2 H 2 atmospheres. The highly ionized metal vapor was deposited onto polished substrates (molybdenum, AISI D2 steel), forming a nearly particulate-free, very smooth and dense film structures, which can be hardly reached by using other PVD techniques. The variation of the gas flow during deposition causes a change of the chemical composition and the microstructure of the nearly particulate-free coatings, and, consequently, of the mechanical and tribological properties. The solid solution hardening of the fcc TiN lattice by low contents of carbon increases the hardness and elastic modulus, while higher carbon contents decrease this effect. Furthermore, the maximum in hardness and elastic modulus correspond with the minima in the friction coefficients (∼0.2) and wear rates of both the coated disc and the counterparts (AISI 52100 (DIN 100Cr6) ball-bearing steel balls).

The high hardness and the low-wear rates characterize the outstanding tribological behaviour of titanium nitride (TiN) making it to the most widespread material for hard coatings, which were deposited industrially in recent years by employing various deposition methods. For coating of heat sensitive materials and machine parts at low temperatures down to room temperature, only a few deposition techniques can be applied. One of these is the pulsed laser deposition (PLD) method. In this work a multi-spot PLD system with four Nd:YAG laser beams (1064-nm wavelength) was applied to vaporize titanium targets in low-pressure N 2 atmospheres at room temperature. For the deposition of the TiN coatings, high speed tool steel (AISI M2) and corrosion resistant steel (AISI 630 HT) substrates were used. To investigate the differences of film growth in dependency of the target–substrate arrangement, the substrate surfaces were situated parallel (on-axis) and rectangular (off-axis) to the target. The coatings were examined by light-microscopy, scanning electron microscopy, X-ray diffraction, nanoindentation and pin-on-disc tests against ball-bearing steel (DIN 100Cr6/AISI 52100) and alumina (Al 2 O 3 ) counterparts. The results indicate a high influence of the target–substrate arrangement on the textures, residual stresses and hardnesses of the TiN coatings. In spite of these differences all coatings on both on-axis and off-axis placed substrates possess excellent adhesion and high-wear resistance.

Titanium oxide (TiOx) coatings exhibit extraordinary optical, electrical and tribological properties, but very less is known about coatings deposited at room temperature. In the present work this gap was closed by employing the room temperature pulsed laser deposition (PLD) technique. In order to simulate different deposition conditions, the substrate (AISI M2, molybdenum) surfaces were situated parallel (‘on-axis’ geometry) and perpendicular (‘off-axis’) to the pure titanium targets ablated by the Nd:YAG lasers with a wavelength of 1064 nm. The combination of a four-beam PLD evaporator with a suitable movement of the substrates resulted in a high-rate film growth on large surfaces. The coating structure investigated by X-ray diffraction consists of a mixture of monoclinic β-TiO2 and amorphous TiOx phase. The ratio of the amount of the phases, the hardness and the elastic constants strongly depend on the O2 gas pressure and the target–substrate arrangement applied for deposition. Owing to the very high adhesion and their very smooth surfaces, the TiOx coatings exhibit friction coefficients of approximately 0.55 and wear rates of lower than 10−15 m3 N−1 m−1, turning out that titanium oxide coatings deposited by means of PLD are very promising candidates for wear protection applications.

Titanium–aluminium based nitride (Ti,Al)N and carbonitride (Ti,Al)(C,N) hard coating systems possess excellent tribological behaviour in metal cutting and polymer forming contacts. In the present work (Ti,Al)N and (Ti,Al)(C,N) coatings were deposited by employing the pulsed laser deposition (PLD) technique. A pulsed Nd:YAG laser with 1064 nm wavelength was used for the vaporization of TiAl targets in low-pressure N2 or N2/C2H2, atmospheres at room temperature. The highly ionized metal vapour was deposited onto polished substrates (molybdenum, AISI D2). The coatings were characterized by light-microscopy, scanning electron microscopy, X-ray diffraction and hardness tests. The variation of the deposition parameters causes a change of the chemical composition, the texture and crystallinity of the coatings and, consequently, the mechanical properties and tribological behaviour. The latter was characterized in pin-on-disc tests at room temperature by using coated discs and uncoated AISI 52100 (DIN 100Cr6) steel and alumina pins as counterparts. The results demonstrate the excellent industrial applicability of these coatings for cold-forming operations: very low-wear rates were found for the (Ti,Al)N coatings. In contrast, the (Ti,Al)(C,N) coatings possess low-friction coefficients of approximately 0.2. As an outstanding advantage of these coatings, which were deposited at the room temperature by the PLD process, their excellent adhesion to the substrate can be pointed out, reaching the highest level (HF 1) in the Rockwell indentation test.

The aim of the present work is the investigation of the structural, mechanical and tribological properties of low-wear diamond-like carbon (DLC) coatings for industrial applications. Amorphous hydrogen-free (a-C) and hydrogenated (a-C:H) DLC coatings were coated onto various steel substrates (AISI 1045H, B7, H13, D2, M2) with hardness levels varying from 28 to 66 HRC, by employing the pulsed laser deposition (PLD) method. Therefore, graphite targets were ablated with the 1064 nm wavelength of an Nd:YAG laser in argon and C 2 H 2 atmospheres. The high mean laser power of the applied PLD equipment guarantees deposition rates competitive to other physical vapour deposition (PVD) techniques. Because of the specific process conditions and the use of pure titanium adhesive interface layers, coatings with high adhesion to the substrates were produced at room temperature. The investigations of the coatings by means of light and scanning electron microscopy reveals the high surface quality and extremely dense coating structures. XRD measurements indicated the amorphous structure of the coatings. The nature of the chemical bonding was examined by XPS, indicating different amounts of sp 3 carbon bonds. Pin-on-disc tests against 100Cr6 ball-bearing steel balls as counterparts show an excellent wear resistance of a-C and a-C:H DLC coatings on all different steel substrates. These results, demonstrated the applicability of PLD–DLC coatings for wear protection of high precision components in the field of tools and mechanical components.

The Materials Center Leoben Forschung GmbH (MCL) and the Austrian Society for Metallurgy and Materials (ASMET) have jointly organized the "First International Conference on Materials, Processing and Product Engineering - MPPE" held in the Congress Center of Leoben from Nov. 3rd to 5 th, 2015. The main topic of the conference was to present the state of the art in fundamental knowledge and technological expertise enabling and stimulating the development of knowledge based innovations across the entire product value chain starting from the material synthesis, proceeding with the processing of products and concluding with their in-service behaviour until the end of the product life time. Hence, the International Conference on Materials, Processing and Product Engineering MPPE 2015 focused on the core regions of industrial production chains, covering topics such as • Development and characterization of materials; • Materials synthesis and processing; • Dimensioning of components including integrated materials and process modelling; • Behaviour of materials and components during service. The scientific and technological goal was to present the state of the art of theoretical, experimental and numerical techniques and their combinations that are capable of improving the competitiveness of modern production facilities.

The Materials Center Leoben (MCL) is a Competence Center in the field of “Integrated Research in Materials, Process, and Product Engineering”. The MCL provides the manufacturing industry with advanced fundamentals, simulation methods, and experimental techniques in order to promote materials-enabled innovations and to strengthen competitiveness of this sector.

A low-friction and wear resistant TiAlN/VN multilayer coating with TiAlN/VN bilayer thickness 3 nm has been grown by using the combined cathodic arc etching and unbalanced magnetron sputtering deposition on high speed steel tools for dry cutting of aluminium alloys. In this paper, in-lab and industrial high speed milling tests have been performed on an aerospace aluminium alloy 7010-T7651. The results show that the TiAlN/VN coated tools achieved lower cutting forces, lower metal surface roughness, and significantly longer tool lifetime by three times over the uncoated tools as a result of the low friction and eliminated tool-metal adhesion. Under the same conditions, a TiAlN based multicomponent coating TiAlCrYN also increased the tool lifetime by up to 100% despite the high cutting forces measured.

Pressure casting dies are subjected to a large number of thermal as well as mechanical load cycles, which are leading to a characteristic thermally induced crack network on the die surface. As a typical representative for a die material the cyclic thermo-mechanical behavior of the hot work tool steel grade 1.2343 (X38CrMoV5-1) is investigated both experimentally as well as numerically. On the one hand the information from isothermal compression-tension tests is used in a subsequent analysis to calibrate a constitutive model that takes into account the characteristic combined isotropic-kinematic hardening/softening of the material. On the other hand the non-isothermal mechanical response of the material to thermal cycles is characterized by means of a periodic laser pulse applied to a small plate-like specimen which is cooled on the back. The residual stresses developing at the surface of the irradiated region of the specimen are determined ex-situ by means of X-ray diffraction. The obtained values agree well with the results of an accompanying finite-element study. This information is used to verify the calibrated constitutive model. The material law is finally used for the prediction of stresses and strains in a die.

Cyclic thermal loading causes thermal gradients near the loaded surfaces, which are responsible for the development of cyclic strains and mechanical stresses in the sample that subsequently cause accumulated damage. The stress state changes during thermal fatigue loading if plastic strains occur. Most relevant are the formation of tensile stresses, which favour crack nucleation and crack growth, but thermal softening and cyclic softening also play an important role. The combined effect of microstructure, mechanical and physical properties on the thermal fatigue behaviour was studied by testing hot-work tool steels using a testing facility based on a pulsed laser beam. The results indicate that purely martensitic microstructures have a better thermal fatigue resistance than mixed martenitic/bainitic microstructures. High strength seems to be especially beneficial in cases with lower fatigue loads owing to thermal cycling. Higher thermal conductivity plays a beneficial role regarding the thermal fatigue resistance.

PM-tool steels are the most widely used materials for cold forging dies. The lifetime of such dies is mainly controlled by fatigue damage, which consists of the fatigue crack initiation and fatigue crack growth. A special technique was developed in order to characterise the fatigue crack initiation under stress ratios which are typical in cold forging dies. The fatigue cracks are simultaneously generated by the cracking of carbides, debonding of carbide/metallic matrix interfaces or by crack initiation in the matrix. Fatigue crack growth of these high-strength tool steels is plasticity-controlled and comparable to that of ductile materials.