榍石的冲击高压行为与辐照损伤效应对比研究

A Comparative Study on Influence of High-Pressure Shocking and Radiation Damage on Titanite

高压和辐照这两种极端条件会造成晶体材料的晶体结构发生改变或损伤。以榍石(CaTiSiO_5)为研究对象,利用冲击高压和样品回收技术,探索冲击高压作用后结构的变化规律,并与辐照造成的损伤榍石作对比研究,认识冲击高压与辐照造成榍石结构损伤的异同。研究表明:冲击高压作用下,晶态的榍石出现结构损伤和非晶化,出现类似于榍石的辐照损伤现象,但具体过程和受损的晶体结构有明显不同。具体表现为:X射线衍射、红外和拉曼光谱的特征峰强度减弱,谱线变宽,细节丢失;冲击高压导致晶态榍石拉曼光谱的Ti–O伸缩振动主峰出现红移,与辐照损伤蜕晶化过程出现的蓝移相反。此外,晶胞参数a、b、c和晶胞体积V减小,与辐照损伤过程相反。

High pressure shock and α-decay radiation are two extreme conditions capable of leading to damages on crystal lattices of solid materials.The present work investigated the influence of shocking on the structural variations of titanite(CaTiSiO5)using a gas gun shock-wave technology.The results were used to compare the similarities and differences in spectral and structural changes between shocked and α-decay radiation damaged titanite,as α-decay radiation process was considered as involved in a fast high pressure process.The results showed that high pressure shock and α-decay radiation can both produce defective crystal lattice and even amorphous phases in titanite,resulting in a decrease in band intensity,a line boarding and a loss of spectral details in X-ray diffraction patterns,infrared and Raman spectra.However,there are distinct differences in the detailed processes and damage mechanisms between the two processes.Highpressure shock causes the main peak of the Ti-O stretching vibration in titanite shifts to a lower frequency,which is opposite to its behaviour in radiation damaged samples.Furthermore,shocking leads to a reduction of unit cell parameters a,b,c and cell volume V,quite contrary to a unit-cell swelling caused by radiation damage.