Mechanical properties optimization of resin mineral composite for machine tool bed

Resin mineral composite attracted much attention in the field of elementary machine components because of the excellent performance in alleviating vibration. However, applications of resin mineral composite are restricted due to its limited mechanical properties. In this paper, the effects of the aggregate gradation, the maximum diameter of the aggregate, and the mass fraction of the resin on the mechanical strength were investigated. In addition, influences of fiber types (glass fiber and carbon fiber), fiber length, mass content of fiber, and surface treating techniques (ultrasonic cleaning, oxidation by HNO ₃ , coupling treatment by silane) on the mechanical strength of resin mineral composite were also investigated. Experimental results show that the compressive strength of resin mineral composite first increases and then decreases as the maximum aggregate diameter, the fractal dimension of the aggregate gradation, and the resin dosage increase. The best compressive strength was obtained when the maximum diameter of aggregate is 15 mm, the fractal dimension of the aggregate gradation is 2.45, and the mass fraction of the resin is 9%. Results also show that the best mechanical strength was obtained when the lengths of the fibers are 10 mm and the mass fraction of the glass (carbon) fiber is 0.1% (0.05%). Compared with resin mineral composite with no fibers, the compressive strengths of resin mineral composite reinforced by glass fibers and carbon fibers treated with three-step treating technique increased by 16.62 and 14.63%, respectively. And the flexural strength of resin mineral composite reinforced with carbon fibers treated with three-step treating technique increased by 18.3%. The flexural strength of resin mineral composite reinforced with glass fiber treated with two- and three-step treating technique increased by 9.67 and 5.7%, respectively. In addition, the mechanism of the influences of the fiber whose surfaces were treated on the mechanical strength of resin mineral composite was revealed by scanning electron microscopy.