“…Consequently, addition of TiN particles changed the free solidification during WAAM, and reduced the grain refinement and texture strength. Yuan et al [15] pointed out that the weakening of texture strength contributes to the improvement of the performance of the deposition. Figure 3 Texture strength and texture types of (a,d) as-deposition, (b,e) TiN-deposition, and (c,f) TiN + H-deposition.…”
Section: Resultsmentioning
confidence: 99%
“…The diameter of the Al-Zn-Mg-Cu alloy welding wire used in the experiment was 12 mm. The composition of welding wire (weight percentage wt-%) is Al-(6.65) Zn-(2.49) Mg-(2.42) Cu-(0.10) Mn-(0.12) Si [15]. The WAAM equipment consisted of an arc power supply from a YASKAWA six-axis robot and a MASTER TIG3000ACDC VRD welding machine.…”
Section: Methodsmentioning
confidence: 99%
“…The WAAM equipment consisted of an arc power supply from a YASKAWA six-axis robot and a MASTER TIG3000ACDC VRD welding machine. The shielding gas was pure argon (99%); The WAAM experimental parameters were listed as follows: current 105 A, deposition rate 15 mm s −1 , wire feeding rate 73 cm min −1 , shielding gas flow rate 15 L min −1 [15]. The additive deposited part was 200 mm * 65mm * 10 mm.…”
To overcome the strength-ductility trade-off dilemma, the microstructure of Al-Zn-Mg-Cu alloy was controlled by adding TiN nanoparticles and heat treatment successively. Al-Zn-Mg-Cu alloy deposition with both high strength and high elongation was achieved. The tensile strength, elongation, and microhardness were increased by 122.3%, 173.9%, 86.1%, and 82.5%, respectively. The columnar grains were completely transformed into equiaxed grains with the addition of TiN particles and the grain size was reduced by 92.9%. The elongation increase was mainly because of the grain refinement, and the distribution fluctuation of the properties decreased. After T6 heat treatment, the elongation remained high because the grain size changed negligibly. Precipitation strengthening is the main mechanism for the improved tensile strength and hardness.
“…Consequently, addition of TiN particles changed the free solidification during WAAM, and reduced the grain refinement and texture strength. Yuan et al [15] pointed out that the weakening of texture strength contributes to the improvement of the performance of the deposition. Figure 3 Texture strength and texture types of (a,d) as-deposition, (b,e) TiN-deposition, and (c,f) TiN + H-deposition.…”
Section: Resultsmentioning
confidence: 99%
“…The diameter of the Al-Zn-Mg-Cu alloy welding wire used in the experiment was 12 mm. The composition of welding wire (weight percentage wt-%) is Al-(6.65) Zn-(2.49) Mg-(2.42) Cu-(0.10) Mn-(0.12) Si [15]. The WAAM equipment consisted of an arc power supply from a YASKAWA six-axis robot and a MASTER TIG3000ACDC VRD welding machine.…”
Section: Methodsmentioning
confidence: 99%
“…The WAAM equipment consisted of an arc power supply from a YASKAWA six-axis robot and a MASTER TIG3000ACDC VRD welding machine. The shielding gas was pure argon (99%); The WAAM experimental parameters were listed as follows: current 105 A, deposition rate 15 mm s −1 , wire feeding rate 73 cm min −1 , shielding gas flow rate 15 L min −1 [15]. The additive deposited part was 200 mm * 65mm * 10 mm.…”
To overcome the strength-ductility trade-off dilemma, the microstructure of Al-Zn-Mg-Cu alloy was controlled by adding TiN nanoparticles and heat treatment successively. Al-Zn-Mg-Cu alloy deposition with both high strength and high elongation was achieved. The tensile strength, elongation, and microhardness were increased by 122.3%, 173.9%, 86.1%, and 82.5%, respectively. The columnar grains were completely transformed into equiaxed grains with the addition of TiN particles and the grain size was reduced by 92.9%. The elongation increase was mainly because of the grain refinement, and the distribution fluctuation of the properties decreased. After T6 heat treatment, the elongation remained high because the grain size changed negligibly. Precipitation strengthening is the main mechanism for the improved tensile strength and hardness.
“…In wire WAAM, efforts were also made to introduce ceramic particles to refine microstructure and enhance mechanical properties. Yuan et al [17,18] used the surface coating method to add TiN particles in WAAM of the Al-Zn-Mg-Cu alloy. They found that coarse columnar grains were transformed into fine equiaxed grains.…”
In this work, TiC nanoparticles (TiC ps ) reinforced 7075 aluminium alloy was fabricated via an oscillating laser-arc hybrid additive manufacturing process. To show the beneficial effect of TiC ps addition on microstructure and mechanical properties, a conventional 7075 aluminium alloy was also manufactured for comparison. Upon the addition of TiC ps , remarkable grain refinement was achieved with a decrease in average grain size from 111.8 to 12.5 µm, and grain boundary segregation was alleviated. It was also found that many secondary phases precipitated at the grain interior in the deposit with TiC ps . Owing to the refined microstructure and favourable precipitation, as-deposited 7075 aluminium alloy with TiC ps showed enhanced tensile properties of ultimate tensile strengths of 346 and 355 MPa along scanning and build directions.
“…Control of microstructure is essential based on the understanding of solidification behavior in liquid metal processing to obtain high strength and good ductility 1 – 3 . The solidification behavior of liquid metal is influenced by various factors, such as composition, heat flow in the solidifying system, and quality of liquid metal.…”
Grain refinement is a crucial issue in metallic materials. One of the emerging techniques to obtain equiaxed grains is to apply an electric current to the liquid metal during solidification. With this view, in this paper, the effect of electric current on the solidification behavior in various cavity shapes of mold was investigated. Cylinder-, cube-, and cuboid-shaped cavities designed to have similar cavity volume were used. By applying an electric current during the solidification of liquid aluminum, the grains were effectively refined with a grain size of approximately 350 µm for all three types of cavities. The circulating flow of liquid aluminum was observed to have a similar shear rate intensity in all three types of cavities, which is known to be sufficiently high (over hundreds of s−1) to induce dendrite fragmentation resulting newly generated nuclei. Dispersion of nuclei on unsolidified aluminum appeared differently according to the shape of the cavity, which influences final shape of refined zone. The area fraction of refined zone was affected by the relative relationship between the solidification completion time and the electric current application time. This study will provide insight to control of process parameters when electrically-assisted solidification is applied to a real product with a complex shape.
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