top of page

What's Special about Semi-Solid Metal

Updated: Jan 3, 2022

At Vforge our expertise is semi-solid metal (SSM) processing, sometimes called thixoforming, thixoforging, or thixocasting. We process aluminum alloys in the semi-solid state which requires some extra metallurgy along with unique die and system designs. We do this because semi-solid flow offers special advantages over traditional liquid casting. For a start, semi-solid aluminum alloys are viscous (hence the “V” in our name) meaning that they do not splash and spray when entering a die but instead fill the cavity with a smooth, quiescent flow. That in itself is a tremendous asset to avoid entrapping gases inside the part. In addition, because the semi-solid material is typically more than 50% solid at the time of injection, shrinkage porosity is also eliminated. In normal casting situations, when liquid metal transitions to solid in the die or mold, it contracts 6% by volume. Without any external means to fill that deficit, so-called shrinkage cavities can occur. Our combination of semi-solid injection and high, final pressure provide fully dense, pressure tight, and heat-treatable parts.

But it gets better. Because semi-solid metal transfers far less heat to the die than molten aluminum which therefore last longer providing additional benefits to our customers by reducing ongoing tooling replacement costs.

bottom of page