Baoqiang Cong’s research while affiliated with Beihang University and other places

... It is widely used in critical components such as turbine blades, tail cones, and afterburners due to its excellent high-temperature properties and corrosion resistance, with a short-term operating temperature reaching up to 1090 • C [1][2][3]. Selective Laser Melting (SLM) is a key additive manufacturing technique that utilizes a laser beam to melt metal powder layer by layer, enabling the rapid fabrication of complex structural components [4][5][6]. However, the mechanical properties of the SLM-fabricated GH3536 alloy, especially at a service temperature range of 900 • C to 1000 • C, are crucial for determining whether it meets usage requirements. ...

Reference:

Investigation of High-Temperature Tensile Properties and Fracture Mechanisms of GH3536 Alloy Fabricated by Selective Laser Melting

... Wire arc additive manufacturing (WAAM), a wire-based directed energy deposition (DED) approach using electrical arc as the fusion source, has been increasingly popular in industry and academia due to its capability of creating large-sized metal components with high deposition rate. Compared with traditional casting and forging methods, WAAM has significantly higher material utilization and manufacturing efficiency, as well as excellent production flexibility [1,2], which makes it one of the most promising additive manufacturing technologies. To date, WAAM has been widely applied in processing various alloys including titanium alloys, aluminum alloys, steels, nickel-based alloys, and bimetals. ...

Reference:

Depositing Al–Zn–Mg–Cu alloy with different positive electrode/negative electrode ratios of CMT advance process

... The concentrated laser beam enables precise control over the weld pool, which minimizes HAZ's and reduces thermal distortion [77]. Furthermore, it achieves high penetration welds for minimal filler material, beneficial for certain aerospace and automotive applications [78]. While GTAW is slower than LW, it offers superior control over heat input, which is crucial for preventing oxidation and burning of Mg during welding. ...

Reference:

Fundamental review on gas tungsten arc welding of magnesium alloys: challenges, innovations, and future perspectives

... Then, the high plasma pressure leads to the plastic deformation of the near-surface material [35]. By introducing compressive residual stresses (CRS) through plastic deformation, the LSP process can achieve pore closure [36] and grain refinement [37] near the surface of the specimen. Similar effects were also detected in NiTi alloy [38], titanium alloys [39] and stainless steel [40]. ...

Reference:

Tailoring interface properties in wire-arc directed energy deposited dissimilar aluminum alloys through interlayer laser shock peening

... This improvement can be attributed to multiple factors, including grain refinement, disruption of continuous precipitates, and the introduction of various strengthening mechanisms. Wang et al. [15] explored the microstructural controlling effects of the TiC particle addition and found a 0.48 w.t.% of TiC can increase the UTS and elongation by 27.2% and 319%, respectively, without forming clusters at the grain boundaries. Wang et al. [16] combined TiC addition and ultrasonic vibration in the wire arc DED of 7075-Al. ...

Reference:

Microstructure control of ultra-high-strength AlZnMgCu alloys fabricated by wire arc directed energy deposition: the role of variable polarity electric pulse

... Wire arc additive manufacturing (WAAM), with the advantages of a high material utilisation rate, high deposition rate and low equipment cost, is a special technology used to directly fabricate parts by depositing layers of material [8,9]. Nowadays, WAAM has been used to fabricate NiTi shape memory alloy walls using commercial NiTi wire [10,11]. ...

Reference:

Microstructure and properties of Ni–Ti–Cu alloy fabricated in situ by treble-wire arc additive manufacturing

... The EDS analysis revealed that the impurities on the inner walls of the pores were oxides of the alloying elements, indicating the coexistence of the pores and oxides. A similar phenomenon has been observed in the welding of aluminum matrix composites, where TiC particles are distributed on the inner walls of circular pores [41]. The varying solubility of hydrogen in aluminum was found to be a significant factor contributing to these micro-elliptical pores [7]. ...

Reference:

On-line laser shielding of hydrogen-induced pores in arc-directed energy deposition

... Despite these advancements, the interplay between additive manufacturing processes, such as DED-Arc, and advanced post-processing techniques like LSP remains insufficiently understood. In particular, the impact of LSP on the microstructural and mechanical properties of stainless steel 308L fabricated using DED-Arc has not been extensively investigated [20]. Addressing this gap is crucial for optimizing the mechanical performance of 308L stainless steel, which is essential for applications requiring high strength, durability, and material efficiency. ...

Reference:

Enhance the microstructure and mechanical properties of directed energy deposition-Arc (DED-Arc) stainless steel 308L using laser shock peening process

... Also, Cu reduces the hydrogen treatment is usually performed, involving a solution treatment followed by artificial ageing. During the solution treatment, the alloy is heated up to 495-523 • C [20,21] to dissolve Cu-and Mg-rich phases [22,23], avoiding any local melting. The subsequent quenching prevents the precipitation of the dissolved elements, while the artificial ageing performed in the range 165-210 • C [24,25] leads to the formation of well-dispersed coherent or semi-coherent nanoprecipitates such as β′-Mg 2 Si, θ′-Al 2 Cu and Q′-Al 5 Cu 2 Mg 8 Si 6 [9,26,27], that increase the mechanical properties of the α-Al matrix [2,28]. ...

Reference:

In-situ investigation of a heat-treated AlSi7Cu3Mg cast alloy: influence of solidification rate on the cyclic fatigue behaviour

... After the two-stage aging treatment, the mechanical properties of both AC and WC components were substantially improved, while exhibiting excellent strengthening synergies. WC-HT has the optimum properties among the current CMT-WAAMed WE43 alloys as shown in Figure 2(c) [23][24][25][26][27][28][29]. Figure 3 demonstrates the microstructure of WC and AC components before and after heat treatment. As shown in Figure 3(a and b), eutectic phases distributed at grain boundaries can be seen in AC-AD, and the rare earth elements enriched in the eutectic phases give them the highest brightness under SEM. ...

Reference:

CMT wire arc additive manufactured ultra-high strength WE43 alloy via in-situ cooling and precipitation regulating