Microstructures and mechanical performance of Mg–4Si–6Ni–xY in situ composite after extrusion process

Abstract

The microstructures and mechanical properties of the in situ Mg–4Si–6Ni–xY (x = 0, 0.3, 0.6, and 0.9 wt-% Y) composites were studied in this research. Y addition and hot extrusion improved ultimate tensile strength (UTS) and elongation values by refining the grains, Mg₂Si intermetallic and blocky χ-phase within the structure. The addition of 0.9 wt-%Y reduced the grain size from ∼435 to ∼180 µm in the cast state and enhanced the UTS amounts from 159 MPa for the as-cast state to 295 MPa in hot extruded condition. After hot extrusion, grain refinement was an effective strengthening mechanism that increased the toughness values. Microscopic fracture studies displayed several cleavage planes in the cast state and more dimples in the extruded form.

KEYWORDS:

• Mg-based in situ composite
• Y addition
• grain refinement
• intermetallics
• tensile properties
• hot extrusion

Disclosure statement

No potential conflict of interest was reported by the author(s).