Suspensions containing noncolloidal aluminum particles in a Newtonian carrier liquid and the effects of shear history on the rheological properties of suspensions are investigated showing a critical concentration ${\varphi }_c$, which is close to the “freezing” packing fraction of spherical particle suspensions. An apparent liquid-to-solid transition was clearly found for suspensions below ${\varphi }_c$ via transient step shear after long shear history as well as via the large amplitude oscillatory shear flow with controlled shear stress. The microstructures or the local flow characteristics of suspensions with $\varphi <{\varphi }_c$ and with $\varphi >{\varphi }_c$ are still different according to the Fourier Transform Rheological analysis. Although suspensions with $\varphi <{\varphi }_c$ show solidlike behaviors after long shear history, the flow behaviors keep unchanged as shear stress increases, and typically show solidlike, liquid-solid coexistence, liquidlike, and jamming behaviors, successively. However, liquidlike regime of concentrated suspensions with $\varphi >{\varphi }_c$ disappears after preshear.

• Received 11 August 2009

DOI:https://doi.org/10.1103/PhysRevE.80.061404