Toward Enhanced Strength and Ductility of Al–14.5Si Alloy via Solidification Under Super‐Gravity Field

Abstract

Herein, a novel method to improve the mechanical properties of Al–14.5Si alloys via solidification under super‐gravity field is reported. The Al–14.5Si alloys are solidified under normal gravity (1 g) and various super‐gravity fields (1000 g, 2000 g, 3000 g, and 4000 g), respectively. The results indicate that the solidification under super‐gravity field leads to right shifting of eutectic point and significant refinement of the eutectic Si. The refining of eutectic Si has a tremendous influence on mechanical properties. The elongation and fracture toughness of the Al–14.5Si alloys, solidified under super‐gravity field of 3000 g, can reach up to ≈12.7% and ≈20.21 MPa, which are approximately tenfold and three times higher relative to those under normal gravity, respectively. The fracture mode of Al–14.5Si alloy is transformed from brittle fracture under normal gravity to ductile fracture under super‐gravity field.

Influence of Annealing Time on Microstructure and Mechanical Properties of Al-14.5Si Alloy Prepared by Super-Gravity Solidification and Cold-Rolling

“…The refinement of eutectic Si could be achieved by chemical metamorphism (P, Na, Sr, La, Sb and composite modifiers) [ 11 ] and processing regulation (rapid solidification [ 12 ], melt pretreatment, low temperature casting, high pressure crystallization, ultrasonic vibration [ 13 ] and super-gravity solidification [ 14 ], etc. ), which were usually utilized as effective methods to achieve high strength and sufficient ductility.…”

“…), which were usually utilized as effective methods to achieve high strength and sufficient ductility. The submicron eutectic Si could be achieved in Al-Si alloys by super-gravity solidification with a reliable elongation (over 10%) [ 14 ]. Nanoscale Si particles were observed in Al-7Si alloys by high-pressure solution treatment and aging with an excellent ductility (over 15%) [ 15 ].…”