Morphologies of Microstructure in Mg<SUB>97</SUB>Zn<SUB>1</SUB>Y<SUB>2</SUB> Ribbon upon Ageing at Different Temperatures

Abstract

In order to clarify the morphology of the rapidly-solidified (RS)/melt-spun Mg 97 Zn 1 Y 2 (at%) alloy, which has the secondary phases of long-period stacking (LPS) structure, the ribbon was processed with the thickness of 60 mm and the width of 7 mm, and aged (T5 heat-treated) at different temperatures. The as-spun and aged ribbons were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and laser optical microscopy, and micro-hardness measurement were conducted. It is found that there was a cellular/dendritic transition during melt-spinning process of Mg 97 Zn 1 Y 2 alloy, and a mild age strengthening with the hardness of 113HV/0.05 at 573 K; more importantly, there was a different evolution of morphologies of the matrix and inter-metallic compounds from general secondary phase strengthened alloys when age temperatures up to the 773 K had been introduced to the as-spun alloy.

Crystal structure of the mirror symmetry 10H-type long-period stacking order phase in Mg–Y–Zn alloy

“…In recent years, Mg-Y-Zn alloys have received considerable attention due to their excellent mechanical properties and unique microstructures [11][12][13][14][15][16][17][18][19][20]. In particular, various novel lamellar structure of long-period stacking order (LPSO) phases have been observed, including 6H, 10H, 14H, 18R and 24R [21][22][23][24][25][26][27][28][29][30][31]. The 6H and 14H structure are commonly observed in conventional casting production [22], while 18R is the main phase by rapid solidification (RS) processing [23].…”

Microstructure and Mechanical Properties of Mg–RE–TM Cast Alloys Containing Long Period Stacking Ordered Phases: A Review

“…Therefore, fine and dispersedly distributed 18R LPSO phase is more prone to dissolving into the matrix during annealing. Furthermore, in the case of the same alloy prepared by rapid solidification, the evolution behavior of LPSO phase becomes more complicated [42,44].…”

“…As a result of the synergistic strengthening effects of solid solution strengthening, fine-grained strengthening, second-phase strengthening and precipitation strengthening, Mg-RE-Zn alloys with LPSO phase exhibit superior mechanical properties at room and elevated temperatures than commercial casting magnesium alloys. So far, various processing techniques, such as rapidly solidification [5,[39][40][41][42][43][44][45], directional solidification [46][47][48][49][50][51][52][53], solid solution treatment [54][55][56][57], aging [21,32,33,[58][59][60], and so on [61][62][63][64][65][66], have already been performed on LPSO-containing cast alloys to tailor their microstructures and properties. To further provide a guidance on the development of high-performance LPSOcontaining Mg-RE-Zn cast alloys with low cost and broad applications, it is imperative to understand the relationships of microstructural evolutions, processing methods and mechanical behaviors.…”