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Understanding the nucleation and growth of polycrystalline thin films is a long-standing goal. Numerous studies have been done to determine the grain size, stress, and the ideal crystallographic orientation in films. The majority of past studies have either employed an ex-situ methodology or only monitor the development of macroscopic stress in real-time. There has never been any research done on the simultaneous changes in crystallographic texture, grain size, and microscopic stress in polycrystalline thin films. In this study, we investigated the generation and temporal evolution of texture, grain size, and internal stress in cathodic arc evaporated Al0.50Ti0.50N thin films using a bespoke deposition apparatus designed for use with 2-dimensional synchrotron x-ray diffraction technique. The influence of the substrate temperature is investigated in terms of the emergence and development of texture, grain size and stress evolution. A dynamic evolution of the crystallographic texture is observed as the overall film thickness varies. We clearly resolved two regime of films growth based on stress evolution. Beyond a threshold grain size (similar to 14 nm), the stress scales inversely to the average grain sizes, and as the film thickness increases, immediate compressive stress relaxation was seen. An extensive ex-situ evaluation of thin films using electron microscopies and electron diffraction was performed to support the in-situ x-ray diffraction results., Funding Agencies|Swedish Research Council [2017-06701]; Vinnova [2022-03071]; Swedish government strategic research area grant AFM (SFO Mat LiU) [2009-00971]

The wurtzite phase of TiAlN has been known to form in industrial grade coatings with high Al content; yet, a significant knowledge gap exists regarding its behavior at high temperatures and the impact of defects on its properties. Specifically, its response to high temperatures and the implications of defects on its characteristics are poorly understood. Here, the high-temperature decomposition of nitrogen-deficient epitaxial wurtzite Ti1-xAlxNy (x = 0.79-0.98, y = 0.82-0.86) films prepared by reactive magnetron sputtering was investigated using x-ray diffractometry and high-resolution scanning transmission electron microscopy. The results show that wurtzite Ti(1-x)Al(x)Ny decomposes by forming intermediary MAX phases, which then segregate into pure c-TiN and w-AlN phases after high-temperature annealing and intermetallic TiAl nanoprecipitates. The semicoherent interfaces between the wurtzite phase and the precipitates cause age hardening of approximately 4-6 GPa, which remains even after annealing at 1200 degrees C. These findings provide insight into how nitrogen vacancies can influence the decomposition and mechanical properties of wurtzite TiAlN., Funding Agencies|The authors acknowledge the support of ViNNOVA (FunMat-II Project Grant No. 2016-05156), the Swedish Research Council (VR Grant Nos. 2017-03813, 2017-06701, and 2021-00357), and the Swedish government strategic research area grant AFM-SFO MatLiU (No. 2009- [2016-05156]; Swedish Research Council (VR) [2021-00357]; Swedish government strategic research area grant AFM-SFO MatLiU [2009-00971]

The aim of this thesis is to understand and control how the ions in the plasma influence the film growth during thin film deposition processes. Two physical vapor deposition (PVD) techniques are investigated, namely magnetron sputtering and cathodic arc evaporation. For magnetron sputtering, the unconventional hybrid high-power impulse and direct current magnetron cosputtering (HiPIMS/DCMS) configuration is used in this work. By synchronizing the substrate bias pulses with the HiPIMS pulses by a time offset and duration, the metal ions from the target material can be selected to impinge the growing film, whereas the contribution of the working gas ions can be effectively reduced. Two aspects are explored, low-mass ion subplantation and heavy-mass ion irradiation. The thesis begins with establishing the correlation between N2 pressure and plasma properties of the cathodic arc evaporation process using Ti0.5Al0.5 target. The results show Ti ions are the dominant species, followed by Al+. On the other hand, due to the shorter mean free path of the species with increasing N2 pressure, the ion energies and the effective electron temperature decrease while electron density increases. Consequently, comparing the TiAlN coatings grown at lower and higher N2 pressures, the crystallographic textures changes from cubic 220 to 111 along the growth direction, and the residual stress reduces from compressive (-3.4 GPa) to almost stress-free (0.6 GPa). The rest of the thesis addresses the influence of ionized species on microstructures, with a focus on tuning film properties by ions in the plasma. Ti1-x(AlySi1-y)xN coatings (0.38 < x < 0.76 and 0.68 ≤ y ≤ 1.00) were deposited with an AlSi-HiPIMS/Ti-DCMS with synchronized substrate bias setup. The results show that the coatings deposited by this method have higher Al and Si solubilities in NaCl-structured TiN than other PVD techniques due to low mass ion subplantations. Additionally, a range of films with different composition

A combined high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) technique is used to deposit Ti0.6Al0.32Si0.08N films with 1-fold substrate table rotation. Layers are grown at two different substrate-target separations, two different rotational speeds, and with different values of substrate bias. The aim is to study the role of (1) overlap between ion and neutral fluxes generated from HiPIMS and DCMS sources, respectively, and (2) the subplantation range of low-mass ions. Results from X-ray diffractometry highlight the necessity of flux intermixing in the formation of the metastable B1-structured TiAlSiN solid solutions. All films grown at short target-to-substrate distance contain the hexagonal AlN phase, as there is essentially no overlap between HiPIMS and DCMS fluxes, thus the Al+ and Si+ subplantation is very limited. Under conditions of high flux intermixing corresponding to larger target-to-substrate distance, no w-AlN forms irrespective of rotational speed (1 or 3 rpm) and bias amplitude (120 or 480 V), indicating that the role of Al+/Si+ and Ti flux overlap is crucial for the phase formation during film growth by HiPIMS/DCMS with substrate rotation. This conclusion is further supported by the fact that the reduction of the bilayer thickness with increasing the target-to-substrate distance (hence increasing flux overlap) is larger for films grown with higher amplitude of the substrate bias, indicative of more efficient Al+/Si+ subplantation into the c-TiN phase. Single-phase films with the hardness close to that of layers grown with stationary substrate table can be achieved, however, at the expense of higher compressive stress., Funding: VINNOVA (FunMat-II project) [2016-05156]; Swedish Research Council [2017-03813, 2017-06701]; Swedish government strategic research area grant AFM - SFO MatLiU [2009-00971]

Although titanium nitride (TiN) is among the most extensively studied and thoroughly characterizedthin-film ceramic materials, detailed knowledge of relevant dislocation core structures is lacking. Byhigh-resolution scanning transmission electron microscopy (STEM) of epitaxial single crystal (001)-oriented TiN films, we identify different dislocation types and their core structures. These include, besidesthe expected primary a/2{110}h110i dislocation, Shockley partial dislocations a/6{111}h112i and sessileLomer edge dislocations a/2{100}h011i. Density-functional theory and classical interatomic potentialsimulations complement STEM observations by recovering the atomic structure of the different disloca-tion types, estimating Peierls stresses, and providing insights on the chemical bonding nature at the core.The generated models of the dislocation cores suggest locally enhanced metal–metal bonding, weakenedTi-N bonds, and N vacancy-pinning that effectively reduces the mobilities of {110}h110i and {111}h112idislocations. Our findings underscore that the presence of different dislocation types and their effects onchemical bonding should be considered in the design and interpretations of nanoscale and macroscopicproperties of TiN., Funding: Swedish Research Council [2017-03813, 2017-06701, 2021-04426, 202100357, 2019-00191]; VINNOVA [2016-05156]; Swedish government strategic research area grant AFM -SFO MatLiU [2009-00971]; Knut and Alice Wallenberg Foundation (Wallenberg Scholar grant) [KAW-2018.0194]; Swedish Research Council [2017-03813] Funding Source: Swedish Research Council, FunMat-II

Background The hardware and software differences between MR vendors and individual sites influence the quantification of MR spectroscopy data. An analysis of a large data set may help to better understand sources of the total variance in quantified metabolite levels. Purpose To compare multisite quantitative brain MR spectroscopy data acquired in healthy participants at 26 sites by using the vendor-supplied single-voxel point-resolved spectroscopy (PRESS) sequence. Materials and Methods An MR spectroscopy protocol to acquire short-echo-time PRESS data from the midparietal region of the brain was disseminated to 26 research sites operating 3.0-T MR scanners from three different vendors. In this prospective study, healthy participants were scanned between July 2016 and December 2017. Data were analyzed by using software with simulated basis sets customized for each vendor implementation. The proportion of total variance attributed to vendor-, site-, and participant-related effects was estimated by using a linear mixed-effects model. P values were derived through parametric bootstrapping of the linear mixed-effects models (denoted Pboot). Results In total, 296 participants (mean age, 26 years ± 4.6; 155 women and 141 men) were scanned. Good-quality data were recorded from all sites, as evidenced by a consistent linewidth of N-acetylaspartate (range, 4.4-5.0 Hz), signal-to-noise ratio (range, 174-289), and low Cramér-Rao lower bounds (≤5%) for all of the major metabolites. Among the major metabolites, no vendor effects were found for levels of myo-inositol (Pboot > .90), N-acetylaspartate and N-acetylaspartylglutamate (Pboot = .13), or glutamate and glutamine (Pboot = .11). Among the smaller resonances, no vendor effects were found for ascorbate (Pboot = .08), aspartate (Pboot > .90), glutathione (Pboot > .90), or lactate (Pboot = .28). Conclusion Multisite multivendor single-voxel MR spectroscopy studies performed at 3.0 T can yield results that are coheren

We use a modified cathodic arc deposition technique, including an electromagnetic coil that introduces a magnetic field in the vicinity of the source, to study its influence on the growth of (Ti0.36Al0.64)N coatings. By increasing the strength of the magnetic field produced by the coil, the cathode arc spots are steered toward the edge of the cathode, and the electrons are guided to an annular anode surrounding the cathode. As a result, the plasma density between the cathode and substrate decreased, which was observed as a lateral spread of the plasma plume, and a reduction of the deposition rate. Optical emission spectroscopy shows reduced intensities of all recorded plasma species when the magnetic field is increased due to a lower number of collisions resulting in excitation. We note a charge-to-mass ratio decrease of 12% when the magnetic field is increased, which is likely caused by a reduced degree of gas phase ionization, mainly through a decrease in N2 ionization. (Ti0.36Al0.64)N coatings grown at different plasma densities show considerable variations in grain size and phase composition. Two growth modes were identified, resulting in coatings with (i) a fine-grained glassy cubic and wurtzite phase mixture when deposited with a weak magnetic field, and (ii) a coarse-grained columnar cubic phase with a strong magnetic field. The latter conditions result in lower energy flux to the coating’s growth front, which suppresses surface diffusion and favors the formation of c-(Ti,Al)N solid solutions over phase segregated c-TiN and w-AlN., Funding agencies: Swedish Research CouncilSwedish Research Council [621-2012-4401]; Swedish government strategic research area grant AFM-SFO MatLiU [2009-00971]; VINNOVA FunMat-IIVinnova [2016-05156]

Using first principles calculations and experimental methods we show that B1 structured solid solution TixNbyAlzN can be grown. The mixing free energy surface indicates that the alloys should decompose. Theoretical analysis of the thermodynamic driving force towards the spinodal decomposition shows that the force can be different in alloys with equally low thermodynamic stability but different Nb content, indicating that the detailed picture of the decomposition should also be different. Electron microscopy and nanoindentation underlines different age hardening of the samples. We demonstrate that an alloy with the optimized composition, Ti0.42Nb0.17Al0.41N combines high thermal stability and age hardening behavior., Funding Agencies|VINN Excellence Center Functional Nanoscale Materials (FunMat-II) [201605156]; Swedish Research Council (VR) [201504391]; Swedish Foundation for Strategic Research (SSF) program [621-2012-4401]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Vinnova [201302355]; Ministry of Education and Science of the Russian Federation [14.Y26.31.0005, K2-2017-080, 211]