铝硅准二元玻璃硬度和抗碎裂性演化的结构起源

Structural Origin of Hardness and Crack Resistance in Aluminosilicate Glass

为探究准二元铝硅玻璃硬度和抗碎裂性随组分变化的结构起源,采用激光加热气动悬浮技术,制备了组分为x Al_(2)O_(3)·(100-x)SiO_(2)(30≤x≤63,摩尔分数)的系列玻璃样品。利用显微维氏硬度仪对玻璃的硬度、抗碎裂性进行了详细表征。结果表明:随着Al_(2)O_(3)含量增加,玻璃硬度逐渐升高,于x=63时硬度最大(8.94GPa);而玻璃的抗碎裂性随Al_(2)O_(3)含量的增加呈现非线性变化,并于x=63时出现最大的抗碎裂性(19.49 N)。结构解析发现:随着Al_(2)O_(3)含量增加,原子堆积密度和平均场键能密度的升高是导致玻璃硬度上升的原因;存在分相的玻璃中相界面可有效提升玻璃的抗碎裂性能,而单相均匀玻璃中Al含量的提升亦会明显提升玻璃的抗碎裂性,这两者之间的协同和相互竞争是准二元铝硅体系玻璃抗碎裂性出现非线性变化的结构根源。莫来石相区组分的玻璃结构类似,抗碎裂性未发生明显的变化。

Utilizing a laser-heated aerodynamic levitation melting technique,we prepared a series of aluminosilicate glasses(x Al_(2)O_(3)·(100-x)SiO_(2),30≤x≤63,in molar fraction).The Vickers hardness(HV)and crack resistance(CR)of the glasses were investigated by a micro-hardness Vicker tester.The results show that the hardness of those glasses increases gradually with the increase of Al_(2)O_(3) content,and the maximum hardness is 8.94 GPa as x=63.However,the crack resistance of the glasses is nonlinear with the change of composition,and the maximum crack resistance is 19.49 N as x=63.According to the results of structural analysis,the increase of atomic packing density and mean-field bond energy density can be attributed to the hardness enhancement.The reduction of the phase interface can lead to the reduction of the crack resistance,while the increase of Al_(2)O_(3) content in the glass can result in an increase in the crack resistance.The synergy and competition between the phase interface reduction and Al_(2)O_(3) content increase can result in a nonlinear change of crack resistance.The crack resistance does not change significantly due to the similar structures of the glasses within the mullite phase region.