(Y, Gd)H2 phase formation in as-cast Mg-6Gd-3Y-0.5Zr alloy

Abstract

In this work, a new (Y, Gd)H 2 precipitate was identified and systematically investigated in the ascast Mg-6Gd-3Y-0.5Zr alloy by XRD, SEM with EDS, TEM with EDS techniques and thermodynamics analysis. Results show that the as-cast alloy contains α-Mg, Mg 24 (Gd, Y) 5 , and (Y, Gd)H 2 phase. The (Y, Gd)H 2 phase usually forms near the eutectic phase Mg 24 (Gd, Y) 5 or in the α-Mg grains, displaying a rectangle-shape. The Mg 24 (Gd, Y) 5 and (Y, Gd)H 2 phases crystalize in bcc and fcc structure, respectively, and the (Y, Gd)H 2 phase has a semi-coherent relationship with α-Mg matrix. The thermodynamics calculation results reveal that the hydrogen dissolved in the melt leads to the formation of hydrides. It is also found that the (Y, Gd)H 2 hydride can form directly from the liquid phase during solidification. Additionally, it can precipitate by the decomposition of Mg 24 (Gd, Y) 5 phase due to absorbing hydrogen from the remaining melt.

Effect of aging temperature on the microstructure and properties of alloyed high‐manganese steel

“…For many years, scholars have used many ways to improve the wear resistance of high manganese steel. Such as alloying, age-strengthening, surface plastic deformation strengthening, precipitation strengthening [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. However, the initial wear resistance of the water-toughened high manganese steel is low.…”

“…For example, chromium, aluminum, and various elements and trace rare earth elements are added to improve wear resistance [17][18][19]. After alloying treatment, the yield strength and tensile strength of high manganese steel can be increased by about 40 % and 27 %, respectively [3].…”