RESUMO
A laser power bed fusion (L-PBF) manufacturing process was optimized by analyzing the surface morphology and track width w of single scan tracks (SSTs) on Fe-3.4wt.%Si. An SST was evaluated under process conditions of laser power P, scan speed V, and energy density E = P/V. The SST surface shape was mainly affected by E; desirable thin and regular tracks were obtained at E = 0.3 and 0.4 J/mm. An L-PBF process window was proposed considering the optimal w of SST, and the appropriate range of E for the alloy was identified to be 0.24 J/mm to 0.49 J/mm. w showed a strong relationship with E and V, and an analytic model was suggested. To verify the process window derived from the appropriate w of SST, cubic samples were manufactured with the estimated optimal process conditions. Most samples produced had a high density with a porosity of <1%, and the process window derived from SST w data had high reliability. This study presents a comprehensive approach to enhancing additive manufacturing for Fe-3.4Si alloy, offering valuable insights for achieving high-quality samples without the need for time-intensive procedures.
RESUMO
In recent year, vanadium-doped tribological films have become available as possible candidates for self-lubrication at high temperatures. In this work, quaternary Al-Cr-V-N films were deposited onto silicon wafer and WC-Co substrates by an unbalanced magnetron sputtering using high purity (99.99%) CrAl2 and V targets with argon-nitrogen reactive gases. EPMA results revealed that vanadium atoms can incorporated from 0 to 13 at.% into the films. The maximum hardness value was ~32 GPa at vanadium content of 7.1 at.% in the Al-Cr-V-N films. The high-temperature tribometer was used to analysis the friction characteristics of the films with elevated temperature. As a result of the high temperature friction test after heating up to 700 °C, the average friction coefficient decreased from 0.62 to 0.35 with increasing of vanadium contents in the Al-Cr-V-N films. It is concluded that the reduction of the friction coefficient is attributed to the formation of V2O5, which is a Magnéli phase that acts as a lubrication at high temperature.
RESUMO
Multi-functional quinary Cr-Al-Ti-Si-N thin films were deposited onto WC-Co substrates using a cathodic arc evaporation system. In this study, the influence of silicon contents on the microstructure, mechanical, tribological, and oxidation properties of Cr-Al-Ti-Si-N thin films were systematically investigated and correlated for application of cutting tools. Based on results from various analyses, the Cr-Al-Ti-Si-N films showed excellent properties including mechanical, tribological, oxidation and adhesion values compared with those of the Cr-Al-Ti-N film. The Cr-Al-Ti-Si-N films with a Si content of around 4.21 at.% exhibited the highest hardness of 45 GPa, very low friction coefficient of 0.38 at room temperature against an Inconel alloy ball and superior adhesion property (105 N). The Cr-Al-Ti-Si-N films also showed excellent oxidation resistance after annealing in the ambient air at 1000 °C. Therefore, the Cr-Al-Ti-Si(4.21 at.%)-N films could be help to improve the performance of machining and cutting tools with application of the films.
RESUMO
High temperature oxidation behavior of nanocomposite films is very important characteristics for application of machining and cutting tools. Quaternary Cr-Al-Si-N nanocomposite films with various compositions were deposited onto WC-Co and Si wafer substrates using a filtered arc ion plating technique. The composition of the films were controlled by different combinations of CrAl2 and Cr4Si composite target power in a reactive gas mixture of high purity Ar and N2 during depositions. The instrumental analyses revealed that the synthesized Cr-Al-Si-N films with Si content of 2.78 at.% were nanocomposites consisting of nano-sized crystallites (3-7 nm in dia.) and a thin layer of amorphous Si3N4 phases. The nanohardness of the Cr-Al-Si-N films exhibited the maximum values of ~42 GPa at a Si content of ~2.78 at.% due to the microstructural change to nanocomposite as well as solid-solution hardening. The Cr-Al-Si-N film shows superior result of oxidation resistance at 1050 °C for 30 min in air. Based on the XRD and GDOES analyses on the oxidized films, it could be revealed that the enrichment of Al (17.94 at.%) and Cr (26.24 at.%) elements in the film leads to form an Al2O3 and Cr2O3 layer on the Cr-Al-Si-N film surface. Therefore, in this study, the microstructural changes on the mechanical properties and oxidation behavior with various compositions in the Cr-Al-Si-N nanocomposite films were discussed and correlated with the deposition parameters.
RESUMO
Oxidation behavior of nanocomposite films is very important characteristics for application of machining and cutting tools. In this study, Ti-Al-Si-N-O nanocomposite films were fabricated onto WC-Co and Si wafer substrates. The composition of the Ti-Al-Si-N-O films was analyzed by X-ray photo-electron spectroscope (XPS). Also X-ray diffactometer (XRD) analysis was conducted to investigate the crystallinity and phase transformation of the films. As a result of XRD, Ti-Al(18 at.%)-Si-N-O films showed the great oxidation resistance of 950 °C for 30 min in air. Based on glow discharge optical emission spectroscopy (GDOES) depth profiles, Ti-Al(18 at.%)- Si-N-O film annealed at 950 °C for 30 min shows formation of aluminum oxide layer on the film surface. On the other hand, Ti-Al(7.56 at.%)-Si-N-O film had a titanium oxide layer on the surface after annealing at 950 °C for 30 min.
RESUMO
Functional graded Ti-Al-Si-N-O nanocomposite films were deposited onto WC-Co substrate by a filtered arc ion plating system using TiAl and TiSi composite targets under N2/Ar atmosphere. XRD and XPS analyses revealed that the synthesized Ti-Al-Si-N-O films were nanocomposite consisting of nanosized (Ti, Al, Si)N crystallites embedded in an amorphous Si3N4/SiO2 matrix. The hardness of the Ti-Al-Si-N-O films exhibited the maximum hardness values of ~47 GPa at a Si content of ~5.63 at.% due to the microstructural change to a nanocomposite as well as the solid-solution hardening. Besides, Ti-Al-Si-N-O film with Si content of around 5.63 at.% also showed perfect adhesive strength value of 105.3 N. These excellent mechanical properties of Ti-Al-Si-N-O films could be help to improve the performance of machining tools and cutting tools with application of the film. A comparative study on microstructural characteristics among Ti-Al-Si-N-O films with various Si contents is reported in this paper.
RESUMO
Quinary Ti-B-C-N-Si nanocomposite films were deposited onto AISI 304 substrates using a pulsed d.c. magnetron sputtering system. The quinary Ti-B-C-N-Si (5 at.%) film showed excellent tribological and wear properties compared with those of the Ti-B-C-N films. The steady friction coefficient of 0.151 and a wear rate of 2 × 10-6 mm3N-1m-1 were measured for the Ti-B-C-N-Si films. The oxidation behavior of Ti-B-C-N-Si nanocomposite films was systematically investigated using X-ray diffraction (XRD), and thermal analyzer with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It is concluded that the addition of Si into the Ti-B-C-N film improved the tribological properties and oxidation resistance of the Ti-B-C-N-Si films. The improvements are due to the formation of an amorphous SiOx phase, which plays a major role in the self-lubricant tribo-layers and oxidation barrier on the film surface or in the grain boundaries, respectively.