Shock-loading meteoritic b.c.c. metal above the pressure transition: Remanent-magnetization stability and microstructure     

Peter Wasilewski 《Physics of the Earth and Planetary Interiors》1976,11(3):P5-P11

Three discrete levels of remanent-magnetization stability with associated microhardness and microstructural detail are recognized in meteoritic b.c.c. metal (α or kamacite) which has been shock loaded to peak pressures in excess of that required for the first-order crystallographic transformation. The first level ($\text{100}\text{kbar}\text{? P ? 200}\text{kbar}$) with moderately high magnetic stability is associated with shock transformation hardening in the absence of significant thermal effects. The second level ($\text{400}\text{kbar}\text{? P ? 600}\text{kbar}$) with low magnetic stability is characterized by decreasing hardness, finely structured metal, and minor recrystallization — evidence of thermal effect notably recovery. The third level ($\text{P ? 800}\text{kbar}$) with the highest magnetic stability has hardness values characteristic of an alloy quenched from ～ 1,000°C. There is extensive fine-scale recrystallization and some areas have the appearance of massive martensite. The first level is associated with shock transition remagnetization i.e., simply a consequence of the ? (antiferromagnetic) → α (ferromagnetic) reversal. The second and third regions contain a thermal component.  相似文献   

Preliminary results of an experimental study of the magnetic effects of shocking lunar soil     

M. Fuller  F. Rose  P. J. Wasilewski 《Earth, Moon, and Planets》1974,9(1-2):57-61

Preliminary shock experiments at approximately 50 and 250 kb have been carried out with lunar soil and with a dispersion of iron in quartz. The lunar soils acquire remanent magnetization in the Earth's field of order of magnitude 10^?3 G cm³ g^?1. The remanence exhibited considerable stability against AF demagnetization. Remanence appears to be acquired both during the passage of the shock wave through the material and during post shock cool-down. The higher shock range gave rise to an increase in magnetic viscosity and in the saturation magnetization of the soil, which is most readily explained as due to the generation of fine grained iron.  相似文献