Cu strengthened Al-Si-Cu semi-solid billet fabricated by liquid phase reaction sintering

A high-strength Al-6Si-6Cu semi-solid billet was prepared by liquid phase reaction sintering. Compared with the pure Al grains in the Al-6Si (wt%) semi-solid billet, Cu nanoparticles precipitated in Al grains of the Al-6Si-6Cu (wt%) semi-solid billet. The interface modified by geometrically necessary dislocations (GNDs) makes Cu nanoparticles show a strong pinning effect on dislocations. Under this pinning action, the Al-6Si-6Cu semi-solid billet possesses an outstanding strain-hardening rate, and its yield strength (YS) and ultimate strength (US) increased by 120% and 67.4%, reaching 220 MPa and 360 MPa respectively. The analysis of strengthening mechanism suggests that Orowan strengthening provided by Cu nanoparticles is the main strengthening mechanism of Al-6Si-6Cu semi-solid billet, which provides 83% of the total yield strength.

Automated summary

The Orowan strengthening mechanism provided by Cu nanoparticles in Al-6Si-6Cu semi-solid billet is the main strengthening mechanism, accounting for 83% of the total yield strength.