Synthesis and characteristics of continuous basalt fiber reinforced aluminum matrix composites

Abstract

This study, for the first time investigates the applicability of basalt fiber as a reinforcing material for metal matrix composites through various experimental works for thermal stability and mechanical properties. The residual tensile strength values of basalt fibers after being exposed at different temperatures in a furnace for pre-determined times and/or after being immersed into molten aluminum for different lengths of time were evaluated. Throughout these experimental studies, a processing method for fabrication of these composites was optimized. In this method, basalt preforms were coated with a thin layer of aluminum by immersion into aluminum melt for a short period of time. These laminates were stacked in a mold and consolidated by hot pressing (300℃, 7 min and 630 MPa). The microstructural studies confirmed a good bonding between aluminum and basalt together with a reasonably uniform distribution of fibers within the matrix alloy. Scanning electron microscopy studies revealed the fractured basalt fibers in the matrix alloy as well as occasional improper infiltration of the matrix alloy into the fiber bundles. Consequently, the mechanical properties of aluminum/basalt composites were far inferior to those expected by law of mixtures predictions. However, the strength values of these newly developed metal matrix composites are still adequate for some engineering applications.