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Höganäs AB has a customer center where they perform their cutomers production processes usingtheir own metal powder, thereby gaining knowledge of how the powder behaves and how it can be improved. The powder is usually pressed, and then sintered in a sintering furnace where temperature and atmosphere composition gives the component its desired characteristics. Höganäs AB didn’t save the parameters from these process’s in a easily accessible way, some values were not saved at all. To increase understanding of these parameters impact on the produced detail they wanted these parameters collected and stored in the cloud. They also wanted solution ideas and concepts for implementation of weight measuring on both the in- and output side of the furnace. This project used Ulrich & Eppinger’s product development method, modified by performing continous testing parallell to the design process. The project was also separated into three parts worked on simultaneously. Computer architecture, physical casing and weight measuring. To compile and upload to the cloud a Raspberry Pi 3 B+, a micro processor, was used. It connected via WiFi to upload files to OneDrive. The measured values from the furnace were gathered from the furnace’s PLC via OPCUA and a gas measuring unit via serial communication. Because of the use of metal powder there was conductive dust in the air which could lead to leakage currents and short circuiting if it were to gather on the processor unit. Hence the dust had to be keptaway. The casing was therefore designed to be relatively airtight. The casing was made with 3D-printed PETG. The seal utilized PETG’s elasticity to elastically deform an elevated seal, and thereby sealing the casing, without having to produce more components than a bottom and a lid. The cable feedthrough used the cables elastic deformation to seal. A screen was implemented to start and stop logging processes, which was also sealed using an overlapping lip around it’s rim. The logging of the furnace parameters was split in two logs, a day-log and a job-log. The daylog took measurements continously over a day in long intervals, 30 minutes. At the end of the day a log was uploaded for that day, hence the name. The job-log had to be started manually via the screen and was used to take measurements with higher frequency during a production series. Log files of both types were uploaded to a OneDrive folder. The product was tested with a number of final tests, both for the casing and the software. The casing was tested primarily for the numerical requirements set in the requirements specification. While the software was tested over a longer period of time to ensure functionality.The final product was a sealed, robust, easily disassembled and cable strain relieved 3D-printed box with a 3.5 inch touchscreen and a connected keyboard. It collected the desired data and compiled it to log files readable by programs such as Microsoft Excel. The weight measuring concept produced was a self-made solution with load cells under the loading ramp. The weight is then measured automatically during the regular loading process without disrupting it. Two backup solutions were also put forward.

Titanium aluminides show great technological potential due to their light weight and excellent creep resistance. Their utilisation thus offers a potential to decrease fuel consumption and simultaneously improve the performance of components subjected to stress at high temperatures. However, shaping of titanium aluminides is still a very challenging and costly task considering their brittleness and the sensitivity on chemical composition. Therefore powder metallurgy near-net shape manufacturing techniques are very attractive to decrease material waste and reduce overall processing costs. This research work was focused on the preparation, characterisation and optimisation of creep resistant titanium aluminides for the Metal Injection Moulding (MIM) process. Considering the little information available regarding processing of titanium aluminides by MIM, this work had firstly the goal of assessing the creep behaviour of a reference titanium aluminide alloy. Secondly, alloy variations with compositions based on the reference material were designed with the objective of improving the creep resistance, especially concerning primary creep. The basic strengthening mechanisms applied involved the addition of slow diffusing elements and elements that cause precipitation of hard particles. The specimens were prepared by using pre-alloyed powder and mixtures of a master alloy (pre-alloyed) and elemental powders. Consequently, a great deal of effort was spent in the characterisation of the sintering behaviour in order to achieve reliable test pieces. Even though both methods can deliver sound specimens, the pre-alloyed powder approach led to the best results in terms of residual porosity and microstructural homogeneity. The mechanical testing results indicate that processing of titanium aluminides by MIM is feasible and acceptable creep properties can be achieved with the proper sintering parameters. Even though the ductility at room temperature was considerably limited due to the residual porosity and high amounts of impurities intrinsic to the MIM process, alloys developed within this study showed improved primary creep resistance in the high stress – high temperature regime. In particular alloy variations containing additions of Mo, Si and Gd led to a considerable improvement of the primary creep resistance in comparison to the reference material at 800°C – 350 MPa loading. Titanaluminide zeigen ein großes technologisches Potenzial durch ihre geringe Dichte und hervorragende Kriechfestigkeit. Deswegen kann durch ihre Verwendung der Kraftstoffverbrauch reduziert und gleichzeitig die Gesamtleistung von mechanisch belasteten Hochtemperaturkomponenten verbessert werden. Die Formgebung von Titanaluminiden ist jedoch noch ein sehr schwieriger und kostenintensiver Prozess, vor allem aufgrund der Sprödigkeit und der starken Abhängigkeit der Eigenschaften von der chemischen Zusammensetzung. Daher sind pulvermetallurgische „near-net shape“ Fertigungstechniken sehr attraktiv in Bezug auf Reduzierung des Materialabfalls und der Gesamtverarbeitungskosten. Inhalt diese Arbeit war die Herstellung, Charakterisierung und Optimierung von kriechfesten Titanaluminiden für das Metallpulverspritzguss-Verfahren (Metal Injection Moulding – MIM). Angesichts der wenigen existierenden Informationen über die Verarbeitung von Titanaluminiden durch MIM war das erste Ziel dieser Arbeit die Ermittlung des Kriechverhaltens einer Referenz-Titanaluminid-Legierung. Zweitens wurden Legierungsvarianten auf Basis des Referenzmaterials mit dem Ziel der Verbesserung der Kriechfestigkeit hergestellt, insbesondere in Bezug auf primäres Kriechen. Das Design der Legierungsvarianten basierte dabei auf der Anwendung folgender grundlegender Verstärkungsmechanismen: Zugabe von langsam diffundierenden Elementen und von Elementen, die härtende Ausscheidung bilden können. Die Proben wurden entweder aus vorlegierten Pulvern oder Mischungen aus einer Masterlegierung (vorlegiert) und Elementarpulvern hergestellt. Um eine Überlagerung von fertigungsbedingten Faktoren, wie hohe Porosität, auf die ermittelten mechanischen Eigenschaften auszuschließen, wurde zuerst eine intensive Charakterisierung des Sinterverhaltens durchgeführt. Obwohl mit beiden Methoden geeignete Proben herstellbar waren, führte die Verwendung von vorlegierten Pulvern zu den besten Ergebnissen in Bezug auf Restporosität und Gefüge-Homogenität. Die Ergebnisse der mechanischen Versuche zeigen, dass die Verarbeitung von Titanaluminiden durch MIM möglich ist und eine mit etablierten Herstellungsverfahren konkurrenzfähige Kriechfestigkeit mit den richtigen Sinterparametern erreicht werden kann. Obwohl sich die mit dem MIM Verfahren verbundene Restporosität und den relativ hohen Gehalt an Verunreinigungen negativ auf die Raumtemperaturduktilität auswirkten, zeigten die neuen Legierungen eine verbesserte primäre Kriechfestigkeit im Bereich hoher Spannungen und Temperaturen. Insbesondere die Legierungsvarianten, die Zusätze von Mo, Si und Gd enthalten, führten zu einer erheblichen Verbesserung der primären Kriechbeständigkeit im Vergleich zum Referenzmaterial bei 800°C und 350 MPa Belastung.

The main subject of this work was the investigation of sintering behavior, microstructure, mechanical properties and biocompatibility of metal injection moulded (MIM) Ti-Nb alloys for biomedical applications. Commercially pure titanium (CP-Ti) samples were also fabricated by MIM as a reference. The sintering behavior of MIM Ti-Nb alloys was studied at first, in order to roughly determine the sintering parameters in the following investigations. Dilatometry was applied to investigate the linear shrinkage of MIM Ti-Nb samples from room temperature to 1500 °C at a heating rate of 3 °C/min under argon atmosphere. Various sintering parameters and Nb contents were used to investigate their influences on microstructure and mechanical properties of MIM Ti-Nb alloys by means of density measurements, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical testing. Transmission electron microscopy (TEM) and high energy X-ray diffraction (HEXRD) measurement were applied to investigate the nature and precipitation of the unexpected titanium carbide precipitates in MIM Ti-Nb alloys. Initial cell adhesion and cell proliferation assays of human umbilical cord perivascular cells (HUCPV) on MIM Ti-Nb alloys were performed for biocompatibility characterization. The results of this work show that MIM Ti-Nb and MIM CP-Ti samples have been successfully fabricated and the as-sintered samples show good shape retention without distortion compared to the green sample. The sintering process of MIM Ti-Nb alloys consists of three main steps – Ti-diffusion step, Ti-Nb-diffusion step and Matrix-diffusion step. With increasing sintering temperatures and time, MIM Ti-Nb alloys exhibit lower porosity and higher Young’s modulus. A higher Nb content in MIM Ti-Nb alloys leads to an increase of carbide area fraction and porosity. The three factors – Nb content, carbide area fraction and porosity – determine the mechanical properties of MIM Ti-Nb alloys. An increase of Nb content and amount of carbides as well as a lowered porosity lead to a higher tensile strength. A decrease of Young’s modulus can be expected with higher Nb content and porosity. A high amount of titanium carbides can result in very poor ductility, but annealing and quenching process can significantly improve the elongation by dissolving the carbides. MIM Ti-Nb alloys exhibit good biocompatibility, indicating their potential for implant applications. Das Hauptthema dieser Arbeit war die Untersuchung von Sinterverhalten, Mikrostruktur, mechanischen Eigenschaften und Biokompatibilität von mittels Metallpulverspritzguss (MIM: Metal Injection Moulding) verarbeiteten Ti-Nb Legierungen für biomedizinische Anwendungen. Reintitan (CP-Ti) Proben wurden ebenfalls mittels MIM als Referenz hergestellt. Zunächst wurde das Sinterverhalten der MIM Ti-Nb Legierungen untersucht, um die Sinterparameter für die folgenden Untersuchungen abzuschätzen. Dilatometrie wurde angewendet, um die lineare Schrumpfung von MIM Ti-Nb Proben beim Aufheizen von Raumtemperatur auf 1500 °C mit einer Rate von 3 °C/min unter Argon Atmosphäre zu untersuchen. Verschiedene Sinterparameter und Nb-Gehalte wurden verwendet, um deren Einflüsse auf die Mikrostruktur und die mechanischen Eigenschaften von MIM Ti-Nb Legierungen mit Hilfe von Dichtemessung, optischer Mikroskopie (OM), Röntgenbeugung (XRD), Rasterelektronenmikroskopie (REM) und mechanischer Prüfung zu bestimmen. Transmissionselektronenmikroskopie (TEM) und Hochenergie-Röntgenbeugung (HEXRD) wurden angewendet, um Art und Ausscheidungsprozess der unerwarteten Titankarbide in MIM Ti-Nb Legierungen zu untersuchen. Zur Charakterisierung der Biokompatibilität wurden Tests bezüglich anfänglicher Zelladhäsion und Zellproliferation von perivaskulären Zellen der menschlichen Nabelschnur (HUCPV) auf der Oberfläche von MIM Ti-Nb Legierungen durchgeführt. Die Ergebnisse dieser Arbeit zeigen, dass MIM Ti-Nb und MIM CP-Ti Proben erfolgreich hergestellt werden können. Die gesinterten Proben zeigten eine gute Formbeständigkeit ohne Verzerrung gegenüber des Grünteils. Der Sintervorgang der MIM Ti-Nb Legierungen besteht aus drei Hauptschritten – Ti-Diffusionsschritt, Ti-Nb-Diffusionsschritt und Matrix-Diffusionsschritt. Mit zunehmender Sintertemperatur und Zeit zeigen MIM Ti-Nb Legierungen eine abnehmende Porosität und eine Erhöhung des E-Moduls. Ein höherer Nb Gehalt führt zu einer Erhöhung der Flächenanteile von Karbiden und Poren. Die drei Faktoren – Nb Gehalt, Karbid-Flächenanteil und Porosität – kontrollieren die mechanischen Eigenschaften von MIM Ti-Nb Legierungen. Eine Erhöhung des Nb-Gehaltes und der Menge der Karbide sowie eine geringere Porosität führen zu einer höheren Zugfestigkeit. Eine zusätzliche Verringerung des E-Moduls findet mit höherem Nb-Gehalt und höherer Porosität statt. Eine große Menge an Titankarbiden führt zu einer niedrigen Duktilität, jedoch kann die Dehnung durch Glühen und Abschrecken zur Auflösung der Karbide deutlich verbessert werden. MIM Ti-Nb Legierungen weisen eine gute Biokompatibilität auf und zeigen dadurch ihr großes Potenzial für Implantat Anwendungen.

In den letzten Jahren ist das Interesse, kostengünstig Metallpulver zu kompaktieren, stark gestiegen. Bauteile aus pulvermetallurgisch hergestellten Werkstoffen werden in zunehmendem Maß in der Kraftfahrzeugindustrie, der Luft- und Raumfahrt sowie im allgemeinen Maschinenbau eingesetzt. Eine neue kostengünstige Alternative, um Metallpulver zu kompaktieren, stellt das kontinuierliche Strangpressen dar. Das Hauptanwendungsfeld dieser Technologie ist bisher die Umarbeitung von Gieß- oder Walzdraht aus Aluminium- oder Kupferlegierungen in komplexere Geometrien in einem Arbeitsschritt. Die Verarbeitung von Granulaten oder sogar Pulvern wird derzeit nur vereinzelt durchgeführt und ist daher großtechnisch nicht weit entwickelt. Die kontinuierliche Pulverstrangpresse besteht aus einem rotierenden Rad mit einer umlaufenden Nut und einem stationären Schuh, der als Werkzeugträger dient und eine Extrusionskammer bildet. Das Zuführmaterial wird aufgrund von Reibung in diese Kammer eingezogen. An einem Gegenhalter wird das Material zur Matrize hin abgelenkt. Die einzelnen Pulverpartikel verschweißen aufgrund von Scherkräften zu einem vollständig kompaktierten Strang. Die Reibungskräfte, die durch die Rotation des Extrusionsrades auftreten, erzeugen die erforderlichen Temperaturen und Drücke für die kontinuierliche Extrusion durch die Matrize. Im Rahmen dieser Arbeit werden experimentelle Untersuchungen zum kontinuierlichen Pulverstrangpressen von verschiedenen Aluminiumpulvern durchgeführt. Eine stabile Strangaustrittsgeschwindigkeit und Produktqualität wird erreicht, wenn die Prozessparameter wie Pulverzuführung, Extrusionsradgeschwindigkeit und Prozesstemperatur aufeinander abgestimmt sind. Das Zusammenspiel dieser Parameter ist sehr komplex. Daher wird zusätzlich ein numerisches Modell entwickelt, das den Materialfluss in der Extrusionskammer beschreibt. Zusätzlich wird mit der Finiten Differenzen Methode der Wärmehaushalt des Prozesses und der Extrusionsdruck berechnet. Anhand der experimentellen Untersuchungen und einer Para¬meterstudie am Modell werden grundlegende Erkenntnisse für die Prozessführung bei der Verarbeitung von Metallpulvern gewonnen. Over the past years the interest in compacting economically metal powder is extremely risen. Powder metal parts are used in a progressive rate in the automotive and aerospace industry as well as machine construction. Continuous powder extrusion is a new economically alternative to the conventional extrusion. Usually the continuous extrusion technology is a metal forming process for non-ferrous wires into complex geometries in a single step. A new approach is to use this process with particulate or powder feedstock as an alternative route to conventional powder extrusion which is currently not developed in an industrial scale. The continuous extrusion press consists of a rotating wheel which has a circumferential groove and a stationary shoe which incorporates the tooling and forms an extrusion chamber. The feedstock is drawn into the chamber by frictional grip. An abutment provides an end closure, arresting the forward motion of the feed and forcing the material to flow under right-angle. Discrete powder particles are welded together by shear forces and thus compacted to a fully dense solid. The frictional forces arising from continued wheel rotation generate the temperature and pressure required for continuous extrusion through the die. In this thesis laboratory experiments about continuous powder extrusion with different aluminium alloys are studied. A stable product velocity and quality is achieved if tooling setup and process parameters like powder feeding, wheel speed and process temperatures are optimised. In fact continuous powder extrusion is quite complex. In order to get an insight into the interaction of the various process parameters a model has been developed to describe the material flow in the Conform-extrusion chamber. Additional the heat balance of the process and the extrusion pressure is modelled using a finite difference method. The boundary values of the model are varied and the results are compared to experimental results.

Within this work the relationship between the pore morphology and the fatigue properties of sintered pure iron and steel has been investigated. The mechanical properties of P/M are controlled by their microstructure and the porosity. Many parameters are influencing the microstructure and the porosity. A few of these parameters were considered in the investigation, which will have a significant influence on the performance characteristics of the materials. These parameters are the density, the kind of the powder, the sinter temperature and technique of alloying as well as the composition. The density acts as main parameter because it includes all other parameters. Therefore, the density has the maximum potential for optimizing the properties of the sintered components. The above mentioned parameters influence the morphology of the pores. Due to this, the characterizing of the pore characteristics is very important. The mechanical properties and the porosity have been investigated by varying the density, the sintering temperature and basic powder for sintered pure iron and alloyed steel. The investigated materials were Distaloy AE and SE, pure iron ABC 100.30 and MH 65.17. Basic powder was water atomized and pure broken sponge iron. The sintering conditions were 1120°C and 1280°C in an atmosphere of 70% N2 and 30% H2 in industrial equipment. If the relationship between the geometrical features of the pores and the influencing parameters is known, it is possible to optimize the morphology of the pores by the influencing factors. The base characteristics are pore area and perimeter, convex perimeter, maximum and minimum pore dimensions and the intercepts or distances between the pores. From the primary data a huge variety of secondary quantities can be derived which are used to describe the pore size, the pore shape, and pore interpore space. The pore morphology was quantified by image analysis. According to the results of the image analysis, the majority of all pores is small and rather round. Only a few large pores which are automatically also very irregular can act as potential fracture initiation sites. For this reason 98% of all pores were excluded from the further processing. Only 2% of the remaining larger and most irregular pores were evaluated. Pore irregularities are commonly characterized by a shape factor. The bending fatigue strength was investigated for a varying density by different sintering temperatures and basic powders. For each experimental condition 60 specimens were used in fully reversed flat bending tests at 6 stress levels of which 3 occurred in fracture. The endurance limits were determined for 50% probability at 107 cycles. Many properties of porous sintered materials are related to the pore microstructure. An attempt was made to correlate the fatigue behavior of industrially manufactured sintered iron and steels with quantitative pore characteristics. Crack initiation in fatigue tests was restricted to very few large irregular pores. All efforts to correlate average pore size or shape factors with fatigue strength values yield at best tendencies. Powder laws to describe the relationships between the strength, the density, and the shape factor the coefficients were calculated by regression analysis.

The search for mathematical methods of predicting the increase in density of a metal powder during compaction has attracted numerous scientists, as it is both a technologically interesting and a scientifically challenging problem. This review outlines the way from simple curve fitting approaches to first attempts at constructing physical models which might form a rational basis for the improvement of powder compactibility or compaction procedures. The models described range from considerations of the deformation of a single spherical pore to reasoning in terms of the deformation behaviour of spherical particles in regular and - more recently - random packings. This paper will not deal with the way in which friction affects the distribution of pressure and density in a compact, nor with the effects of lubricants.

A press was built which allows densification to be measured continuously during isostatic pressing of powders at temperatures up to 200 degree C and pressures up to 20 MN/m**2. The press was used to study the densification of lead, tin, and PMMA powders. The dominant mechanisms of densification were found to be plasticity and creep. Large discrepancies were detected between the data and previous models for these mechanisms. Improved models are presented which, while still approximate, include new physical ideas and give a better description of the experiments.