铁冲击相变的晶向效应

发布时间：2018-11-11 15:58

【摘要】：采用基于火炮加载的三样品精细波剖面对比测量,研究了晶向效应对铁弹-塑性转变及体心立方结构(bcc,α相)至六角密排结构(hcp,ε相)相变特性的影响.观测到单晶铁异常的弹-塑性转变行为,这与基于位错密度描述的黏塑性本构模型计算结果相符,对应的Hugoniot弹性极限δ_(HEL)均大于6 GPa,且具有晶向相关性,即δ(111)/(HEL)δ(110)/(HEL)δ(100)/(HEL);系统获取了相变起始压力P_(PT)晶向相关性的实验数据,[100],[110]和[111]晶向的PPT实测值分别为13.89±0.57 GPa,14.53±0.53 GPa,16.05±0.67 GPa,其变化规律与非平衡分子动力学计算结果相符.上述结果揭示出冲击压缩下单晶铁存在塑性与相变微观机理的强耦合,为完善用于冲击实验描述的相场动力学模型提供了重要的实验支撑.
[Abstract]:In this paper, the effect of crystal direction effect on the ferroelastic-plastic transition and phase transition from bcc, 伪 phase to hcp, 蔚 phase is studied by using the contrast measurement of fine wave profile of three samples based on artillery loading. The elastic-plastic transition behavior of single crystal iron anomalies is observed, which is consistent with the calculated results of the viscoplastic constitutive model based on dislocation density. The corresponding Hugoniot elastic limit 未 _ (HEL) is larger than 6 GPa, and has a crystal direction correlation. 未 (111) / (HEL) 未 (110) / (HEL) 未 (100) / (HEL); The experimental data of phase transition initiation pressure (P _ (PT) direction correlation were obtained systematically. The PPT values of [100], [110] and [111] directions were 13.89 卤0.57 GPa,14.53 卤0.53 GPa,16.05 卤0.67 GPa, respectively. The law of variation is consistent with the results of nonequilibrium molecular dynamics calculation. The above results reveal that there is a strong coupling between plasticity and phase transition micromechanism of the ordered iron under impact compression, which provides an important experimental support for the improvement of the phase field dynamics model used for the description of impact experiments.
【作者单位】：中国工程物理研究院流体物理研究所冲击波物理与爆轰物理实验室;
【基金】：国家自然科学基金青年科学基金(批准号:11602251,11302202) 科学挑战专项(批准号:TZ2016001)资助的课题~~
【分类号】：TG141

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