During the recent decades, high-strength-modulus glass fibers have been widely used in aerospace, military defense, wind power generation, transportation, and sports, among other applications [1–3]. Currently, SiO2-Al2O3-MgO glass fibers, which are high in tensile strength, elastic modulus, and impact resistance, among similar products, have received increased attention in the global manufacturing market [4–7]. However, few recent studies have reported the influence of the composition on the mechanical properties of SiO2-Al2O3-MgO glass, let alone the influence of different additives on the mechanical properties of such glass.
The mechanical properties of glass fibers are in close contact with the different additives in the glasses. In order to improve performance, appropriate stabilizers such as rare earth oxides and transition metals are usually introduced into the glass matrix. [8, 9], among which CeO2 is a typical case. Similar to Al2O3-B2O3-SiO2 glasses doped with CeO2, the network structure is improved as the amount of CeO2 increases at under 0.4 mol% [10]. It was also found that the number of bridging oxygen bonds are generated in aluminosilicate glass at a doped molar concentration of 3.5% CeO2 and CeF3, achieving the maximal thermal stability [11]. Cerium presents two different valence states: Ce4+ and Ce3+, due to a ceric-cerous redox equilibrium in a glass structure. A moderate amount of Ce4+ inside the glass can avoid the trapping of electrons produced through a reaction and absorb free electrons, thereby obstructing the formation of permanent defect centers and improving the properties of the glass [12, 13].
In addition, an excessive amount of CeO2 will produce a series of crystallizations as well as non-bridging oxygen, thereby inducing a negative effect on the mechanical properties and drawing process of the glass. It is therefore necessary to add an oxide to make up for the defects of CeO2. The valence states of titanium result in TiO2 playing an important role in the structural properties of glass, suppressing the reduction of Ce4+ into Ce3+ as well as a decrease in the amount of free oxygen, thereby increasing the chemical and mechanical properties [14]. Moreover, it has been suggested that, in a combined incorporation of the cerium and titanium oxides in Li2O-Bi2O3-SiO2 and Na2O-Bi2O3-P2O5 glass, a proper mixing can significantly improve the mechanical properties [15–17].
According to the relatively outstanding properties of SiO2-Al2O3-MgO glass and excellent characterization of TiO2 and CeO2, the effects of TiO2 and CeO2 doping on the mechanical properties of SiO2-Al2O3-MgO glass when changing the amounts of TiO2 and CeO2 are discussed herein.