Laser powderbed fusion (LPBF) is one of the most promising and widely used metal additive manufacturing technology, which is expected to realize the preparation of high-performance complex structure magnesium alloy components to replace traditional casting and plastic deformation technologies.
LPBF has successfully prepared aluminum alloys, titanium alloys, nickel-based superalloys and iron-based alloys with high density and excellent mechanical properties. However, due to the high explosive tendency of magnesium powder, the high saturated vapor pressure and low boiling point of magnesium, LPBF is used It is difficult to prepare magnesium alloys, and there are relatively few research reports. At present, LPBF research on magnesium alloys is mainly aimed at commercial cast magnesium alloy grades (such as AZ91D, AZ31B, ZK60 and WE43, etc.), but these alloy grades are not necessarily suitable for SLM rapid solidification and non-equilibrium processes, so it is necessary to develop SLM special high-performance magnesium alloys Element. Mg-Gd series magnesium rare earth alloys have a significant precipitation strengthening effect and are a type of widely reported high-performance casting and wrought magnesium alloys. The addition of Y element to Mg-Gd series alloys can further improve the mechanical properties and reduce the content of expensive Gd elements. Adding Zn element can introduce a strengthening phase-long period stacking ordered structure (long period stacking ordered, LPSO). Zr element is a commonly used element for grain refinement in Mg-Gd magnesium rare earth alloys. However, no other researchers have reported the evolution of the formability, the microstructure and mechanical properties of the high-strength Mg-Gd-Y-Zn-Zr alloy prepared by LPBF, from the printed state to the solid solution state and then to the aging state. It is necessary to go further. Research. In addition, the use of LPBF to prepare high-performance Mg-Gd series magnesium rare earth alloys is conducive to taking advantage of China’s magnesium and rare earth resources.
Shanghai
transportation
The team of Professor Liming Peng and Associate Researcher Wu Yujuan (corresponding author) of the National Engineering Research Center for Light Alloy Precision Forming of the University took Mg-10Gd-3Y-1Zn-0.4Zr (GWZ1031K, wt.%) as the research object, and systematically characterized the powder and printing State, LPBF-T5 state, LPBF-T4 state and LPBF-T6 state microstructure and mechanical properties. The yield strength, tensile strength and elongation of the LPBF-T6 state are 316 ± 5 MPa, 400 ± 7 MPa and 2.2 ± 0.3%, respectively. The above results were published online on the top issue of Additive Manufacturing under the title “Microstructure evolution and mechanical properties of a high-strength Mg-10Gd-3Y-1Zn-0.4Zr alloy fabricated by laser powder bedfusion”.
Full text link:
https://doi.org/10.1016/j.addma.2021.102517
The average particle diameter of the 200-300 mesh powder is 63.9 μm, most of the powders are regular spherical, there are a small amount of satellite powder and irregularly shaped powder, and there are a large number of small white particles with a diameter of several hundred nanometers on the surface of the powder. EDS pattern It shows that it is an oxide particle.The powder is made of small
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