CAJ | 학술논문

利用分子动力学模拟研究了完美单晶铁以及含不同尺寸孔洞的单晶铁相变过程,分析了孔洞尺寸对相变过程的影响.模拟结果表明:孔洞的存在降低了相变的阈值应力,加速了相变区域成核速率和相变传播速率;随着孔洞直径的增大,相变的阈值应力逐渐降低;孔洞也改变了相变的初始成核区域,使相变区域呈现出一个蝴蝶状的形貌;孔洞反射的稀疏波对相变成核区域的影响随孔洞体积增大而增大,导致孔洞周围出现大量的无序结构原子;孔洞体积对相变的影响也体现在了粒子速度空间分布上,压缩过程中孔洞周围出现的大量"热点"导致了更低的粒子速度空间分布.
이용분자동역학모의연구료완미단정철이급함불동척촌공동적단정철상변과정,분석료공동척촌대상변과정적영향.모의결과표명:공동적존재강저료상변적역치응력,가속료상변구역성핵속솔화상변전파속솔;수착공동직경적증대,상변적역치응력축점강저;공동야개변료상변적초시성핵구역,사상변구역정현출일개호접상적형모;공동반사적희소파대상변성핵구역적영향수공동체적증대이증대,도치공동주위출현대량적무서결구원자;공동체적대상변적영향야체현재료입자속도공간분포상,압축과정중공동주위출현적대량"열점"도치료경저적입자속도공간분포.
The laser shock-induced phase transformation of iron with different volume voids has been investigated by means of molecular dynamics(MD)simulations.By comparing the perfect single crystal iron and the iron with different volume voids,the effects of the void volume have been presented.Simulation results show that the void decreases the phase transformation pressure,and the bigger void induces lower pressure;the increase of void volume speed up the nucleation and the expansion of transformation;the void also changes the initial nucleation district,and makes a butterfly shaped nucleation pattern.The influence of rarefaction wave in bigger void is stronger,which affects phase transformation nucleation sites,and brings on a lot of atoms with amorphous structures.The effect of void volume is also shown in the particle velocity profile by the production of a lot of "hot spots",which lower the particle velocity in the defective iron.