To improve the corrosion resistance and load-bearing performance of titanium alloy, the TiC/Ti based composite coating with good metallurgical quality was prepared on the surface of TC4 titanium ...alloy by using Diode laser, and the effect of TiC content on the microstructures and properties of TiC/TC4 cladding was studied. The microstructure and phase constitution of the coating were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD), the micro-hardness, corrosion resistance and the load-bearing performance of the coatings were evaluated. The results show that the cladding consists of TiC, TiC0.95, NiTi2 and α'-Ti, and the overall hardness of the coating fluctuates greatly. The micro-hardness in hard phases and in the heat affected zone are 1000-1500HV and about 437HV respectively. While the mass fraction of Ni coated TiC is not higher than 60%, higher corrosion resistance of claddings can be obtained with the increase of the mass fraction of Ni coated TiC, reaching a maximum at 60
Additive manufacturing technology(AM) is a new type of manufacturing technology based on the discrete-stacking principle and processing component with computer model data. Selective laser ...melting(SLM) is an important technology in the field of additive manufacturing. With its integrated manufacturing characteristics and significant advantages in the field of complex structural parts manufacturing, it has become a key development technology and frontier direction in the field of aerospace manufacturing. This article reviews the material system and application fields of SLM technology, and mainly analyzes the latest process research of SLM technology and typical applications in the aerospace field. It focuses on the research progress and results of SLM iron-based alloys, nickel-based alloys, titanium alloys and aluminum alloys. While SLM technology is widely used in various fields, there are also many problems and shortcomings, such as many internal defects of forming materials, cracks and deformations of high-
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•Amorphous/crystalline coatings were prepared by laser cladding with rectangular spot.•Laser remelting can decrease cracks, and improve the surface quality of cladding coating.•Laser ...remelting can refine the microstructure and induce the formation of amorphous phases.•Laser remelting can enhance the corrosion resistant and microhardness of cladding coating.
The WC reinforced Fe-based amorphous composite coatings were prepared by laser cladding with rectangular spot. The effect of laser remelting on the microstructure and properties of composite coatings was investigated. The results showed that laser remelting can reduce the cracks and porosities of the cladding coating and improve its surface quality. Large amounts of crystalline phases were precipitated at the top of the cladding and remelting coatings. However, the microstructure at the top of the remelting coating was finer compared to that at the top of the cladding coating. With increasing distance from the surface of substrate, the amorphous phase appeared within the remelting coating and large amounts of carbides rich in Fe and Mo, Fe23B6, γ-Fe and Cr9.1Si0.9 phases were also precipitated in the remelting coating. As a result, the corrosion resistance of the remelting coating was higher than that of the cladding coating. The microhardness of the remelting coating was approximately 1.13 times higher than that of the cladding coating.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•High quality FeCrMoMn coatings were fabricated by high-speed laser cladding.•Mechanism of laser acting on powders during high-speed laser cladding.•Metallurgical behavior of solute trapping during ...rapid solidification of laser molten pool.•Evolution mechanism of corrosion resistance of high-speed laser clad coatings.
In this research, FeCrMoMn coatings with excellent corrosion resistance and metallurgical quality were deposited on the 45# steel substrate by conventional and high-speed laser cladding at the scanning speed of 0.4 m/min, 40 m/min and 70 m/min, respectively. Their microstructure, phase composition, hardness and corrosion resistance were characterized and compared. The results show that compared with the conventional cladding, high-speed laser cladding leads to a decrease in grain size, heat affected zone, and the dilution rate of the coatings due to solute trapping of coatings. Metallurgical bonding is formed between the substrate and the coatings, and the hardness and electrochemical corrosion resistance of the coatings are also significantly improved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This study aimed to modulate the magnetic properties of selective laser melting NiFeMo alloy. This was achieved via the controlled addition of Mo elemental in-situ alloying content to change the ...tissue morphology and crystal structure of SLM-formed (NiFeMo)100−xMox alloy (x = 0 wt%, 0.25 wt%, 0.5 wt%, 0.75 wt%, 1.0 wt%, 1.25 wt%, 1.5 wt%, 2.0 wt%). The results of scanning electron microscopy (SEM), X-ray diffraction, electron backscatter diffraction (EBSD), DC B-H hysteresis tester, and transmission electron microscopy (Titan-G2) indicate that all samples are predominantly face-centered-cubic (FCC) γ- (Ni, Fe) solid solutions and typical soft-magnetic hysteresis line features. However, the lattice parameter a of γ- (Ni, Fe) decreased and then increased with increasing Mo content. When the added Mo content is 0–1.25 wt%, the Mo particles inside the (NiFeMo)100−xMox alloy become nucleation sites, creating a diffusive metallurgical behavior with the Ni and Fe elements, and preventing the growth of columnar crystals, leading to the reduction of LAGBs density and the enhancement of the {111} texture orientation in the easy magnetization direction, increasing Bs and the decrease of Hc of the NiFeMo alloy. At the Mo content of 1.25 wt%, the soft magnetic properties were optimal, with Bs and Hc being 0.704 T and 17.31 A/m, respectively. Conversely, when the added Mo content was 1.5–2.0 wt%, the solubility of Mo elements in the γ- (Ni, Fe) solid solution was limited, which resulted in the occurrence of metallurgical defects within the organization such as unfused Mo particles, unfused areas, and porosity. Moreover, when the added Mo content increased to 2.0 wt%, the {111} lattice spacing in the easy magnetization direction increased by 0.2261 nm compared to the NiFeMo alloy, and the average lattice distortion Δε increased to 0.16%, causing a decrease in the soft magnetic performance of the (NiFeMo)98Mo2 alloy, with Bs reducing to 0.6666 T and Hc increasing to 23.44 A/m.
•The microstructure evolution of NiFeMo alloy formed by in-situ alloy-SLM was analyzed and described in detail.•The crystallographic relationship of NiFeMo alloy with Mo element was analyzed on an atomic scale by HETEM.•Analyzed the changes in soft magnetic properties of NiFeMo alloy with different Mo additions.•Clarified the influencing mechanism of Mo element in-situ alloying on the magnetic properties of NiFeMo alloy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, FeCrNiCoMo maraging stainless steel was fabricated by laser melting deposition. The initial nonequilibrium microstructure exhibited cellular segregation of Cr and Mo with a 10–20 μm ...cell size. We investigated the microstructural evolution, particularly during aging with different time(1 h, 3 h, 5 h), for three post heat treatments: direct aging (500 °C) and low-temperature solution treatment (750 °C) and aging without and with additional prior homogenization (1000 °C). Microsegregation profoundly affected the austenite reversion behavior. The segregation at the cell walls promoted the nucleation and growth of reverted austenite, which eventually linked to form a net-like structure after prolonged aging. The net-like austenite in the direct-aged samples exhibited low thermal stability and result in brittle fracture upon impact at the temperature of liquid nitrogen (−196 °C). Net-like austenite and abundant lath austenite in the cell interior were found in the low-temperature solution-treated samples, which exhibited well-matched strength, toughness, and annealing temperature. Prior homogenization eliminated the microsegregation-induced net-like austenite. The measured mechanical properties indicate that the segregation-induced net-like austenite failed to benefit both the strength and toughness of the studied steel.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The effect of Cr additions on the microstructure and corrosion resistance of CuAl10 coating deposited by laser cladding was investigated. Laser cladding was performed using a 4000 W Diode laser under ...the same conditions, and the premixed powders with different weight ratios of CuAl10 to Cr were fed synchronously by TWIN10C powder feeder and D70 coaxial nozzle. The microstructures were observed under a scanning electron microscope equipped with an energy dispersive X-ray spectrometer (EDS) for chemical analysis, and phase analysis was performed with an X-ray diffractometer (XRD). The electrochemical corrosion behaviors of cladding layers were evaluated. The results showed that the CuAl10 coating has a good metallurgical bonding with the 17-4PH substrate. The addition of Cr can improve the corrosion resistance of CuAl10 coatings, and the passivation ability of the coatings increases with increasing Cr contents. The CuAl10 coating without Cr addition include α, γ2, and K phase; however, the addition of Cr leads to an increase of β′ phase and Cr and a decrease of γ2 and K phase in the CuAl10 coating.
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•CuAl10 coatings with different Cr additions were fabricated by Diode laser cladding.•Microstructure evolution of laser clad CuAl10 coatings with Cr addition.•Corrosion property of laser clad CuAl10 coatings was improved by Cr additions.•Corrosion mechanism of Cr addition was determined by corrosion studies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In order to improve the homogeneity of spherical Fe-rich particles within the Cu-rich matrix, the Cu95Fe5 (wt%) immiscible composite coating has been produced by the combination of mechanical ...alloying and laser cladding. The results show that the milled composite powder presents a polygonal morphology and is mainly composed of face-centered-cubic (fcc)-Cu solid solution. The demixing or delimitation is eliminated in the immiscible composite coating produced by laser cladding and large amounts of spherical α-Fe particles are dispersed within the ε-Cu matrix as a result of liquid phase separation (LPS). The size of the Fe-rich particles measured is in radius of ∼1.5 μm, which is much smaller than the calculated critical radius (∼2.3 μm), confirming that the α-Fe particles containing a supersaturated Cu are driven by the dominant mechanism of Marangoni motion. Compared to Brass, the immiscible composite coating exhibits the improved homogeneous microhardness (153HV0.2) and higher corrosion resistance, as well as a saturated magnetization of ∼9.19 emu/g and low coercivity of ∼9.25 Oe.
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•Homogeneous immiscible coating is produced by mechanical alloying and laser cladding.•Many α-Fe particles with a diameter of ∼3 μm are dispersed within the ε-Cu matrix.•Immiscible coating has higher microhardness and corrosion resistance than Brass.•Immiscible coating exhibits a saturated magnetization of ∼9.19 emu/g.•Immiscible coating exhibits a low coercivity of ∼9.25 Oe.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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