采用嵌入原子势的分子动力学模拟方法,研究了5×10^9 s^–1应变率下,温度效应对单晶铁中孔洞成核与生长的影响,并对NAG(nucleation and growth)模型在单晶铁中的适用性进行了探讨.结果表明:随着温度的升高,单晶铁的抗拉强度峰值降低...采用嵌入原子势的分子动力学模拟方法,研究了5×10^9 s^–1应变率下,温度效应对单晶铁中孔洞成核与生长的影响,并对NAG(nucleation and growth)模型在单晶铁中的适用性进行了探讨.结果表明:随着温度的升高,单晶铁的抗拉强度峰值降低,1100K温度下单晶铁抗拉强度峰值比100 K温度下降低了35.9%.在100-700K温度下,拉应力时程曲线表现出双峰值特点,分析表明,第一峰值是由于拉应力升高引起内部结构发生相变而产生,第二峰值则是因发生孔洞成核与生长而产生;900-1100K温度下,拉应力时程曲线表现为单峰值,孔洞成核与生长是拉应力下降的主要原因.分析发现,孔洞在高温下更容易成核,高应变率下单晶铁中孔洞成核与生长和NAG模型有较好的符合度,单晶铁中孔洞成核阈值与生长阈值都远高于低碳钢,并且孔洞成核阈值与生长阈值随着温度的升高而逐渐降低.研究结果可为建立高应变率下金属材料动态损伤演化模型提供借鉴.展开更多
A biased bimetallic Fe-Fe complex Cp*Fe(dppe)(C≡CFc) (1) was synthesized from FcC≡CH (Fc=C5H4FeC5H5) and Cp*Fe(dppe)Cl (Cp*=C5Me5). Its one-electron oxidation species [Cp*Fe(dppe)(C≡CFc)] (1a) was also prepared and...A biased bimetallic Fe-Fe complex Cp*Fe(dppe)(C≡CFc) (1) was synthesized from FcC≡CH (Fc=C5H4FeC5H5) and Cp*Fe(dppe)Cl (Cp*=C5Me5). Its one-electron oxidation species [Cp*Fe(dppe)(C≡CFc)] (1a) was also prepared and the spectroscopic properties of 1a was studied. The single-crystal X-ray diffraction analysis of 1 shows that ferrocenylacetylene is bonded at the terminal carbon to the iron center in the Cp*Fe(dppe) part. Crystallographic data for 1: monoclinic, space group C2/c, with a=4.067 65(14) nm, b=1.260 74(4) nm, c=1.649 89(5) nm, β=104.387(10)°, V=8.195 7(5) nm3, Z=8, Dc=1.354 g·cm-3, F(000)=3 512, μ=0.822 mm-1. The structure was refined to R1=0.038 4, wR2=0.100 0. CCDC: 234893.展开更多
文摘采用嵌入原子势的分子动力学模拟方法,研究了5×10^9 s^–1应变率下,温度效应对单晶铁中孔洞成核与生长的影响,并对NAG(nucleation and growth)模型在单晶铁中的适用性进行了探讨.结果表明:随着温度的升高,单晶铁的抗拉强度峰值降低,1100K温度下单晶铁抗拉强度峰值比100 K温度下降低了35.9%.在100-700K温度下,拉应力时程曲线表现出双峰值特点,分析表明,第一峰值是由于拉应力升高引起内部结构发生相变而产生,第二峰值则是因发生孔洞成核与生长而产生;900-1100K温度下,拉应力时程曲线表现为单峰值,孔洞成核与生长是拉应力下降的主要原因.分析发现,孔洞在高温下更容易成核,高应变率下单晶铁中孔洞成核与生长和NAG模型有较好的符合度,单晶铁中孔洞成核阈值与生长阈值都远高于低碳钢,并且孔洞成核阈值与生长阈值随着温度的升高而逐渐降低.研究结果可为建立高应变率下金属材料动态损伤演化模型提供借鉴.
文摘A biased bimetallic Fe-Fe complex Cp*Fe(dppe)(C≡CFc) (1) was synthesized from FcC≡CH (Fc=C5H4FeC5H5) and Cp*Fe(dppe)Cl (Cp*=C5Me5). Its one-electron oxidation species [Cp*Fe(dppe)(C≡CFc)] (1a) was also prepared and the spectroscopic properties of 1a was studied. The single-crystal X-ray diffraction analysis of 1 shows that ferrocenylacetylene is bonded at the terminal carbon to the iron center in the Cp*Fe(dppe) part. Crystallographic data for 1: monoclinic, space group C2/c, with a=4.067 65(14) nm, b=1.260 74(4) nm, c=1.649 89(5) nm, β=104.387(10)°, V=8.195 7(5) nm3, Z=8, Dc=1.354 g·cm-3, F(000)=3 512, μ=0.822 mm-1. The structure was refined to R1=0.038 4, wR2=0.100 0. CCDC: 234893.
