Xueshan XIAO
,
Weihuo LI
,
Lei XIA
,
Shoushi FANG
,
Qin HUA
,
Yu
,
a DONG
材料科学技术（英文）
Quasistatic and dynamic tensile behavior of Zr52.5Al10Ni10Cu15Be12.5 bulk amorphous alloy was investigated at the strain rates of 10-4~103 s-1 by using a Shimadzu AG-100KNA autograph and a pneumatic tensile impact tester. It was shown that the tensile fracture strength and the fracture morphology were sensitive to the strain rate. With the increase of the strain rate, the tensile fracture strength decreased and the fracture morphology changed from cleavage into quasi-cleavage, and then into a mixture of microvoid-coalescence dimples and quasi-cleavage veins.
关键词:
Mechanical properties
,
null
,
null
Yuanzheng YANG
,
Qiaoshen LI
,
Youlan ZHU
,
Xueming MA
,
Yu
,
a DONG
材料科学技术（英文）
Amorphous and nanostructural Fe-B alloys made by mechanical alloying of elemental Fe and amorphous B powders have been studied using X-ray diffraction, differential scanning calorimetry and Mössbauer spectroscopy. It has been shown that the milling conditions have a strong effect on the alloying. The single-phase amorphous alloy, which is limited at nominal composition of Fe60B40, has been produced only by milling in Ar atmosphere and in other composition range the mixture of nanostructure Fe-like phase and Fe2B compound with a little amorphous phase are obtained. While by milling in air atmosphere the introduction of oxygen in air may suppress the formation of amorphous phase, thus the compounds Fe2B may be synthesized with no trace of amorphous phase. The crystallization temperatures of amorphous phase in the resultant products are higher than those of a single amorphous alloy Fe60B40, and hardly independent of the milling conditions and the composition. In addition, it is revealed that detectable B content in the final products is lower than the nominal composition of all the initial samples, which indicates that some B atoms may be located in the disordered interfacial regions of the nanostructural alloyed mixtures.
关键词:
Physical Review B
In a recent publication [S. Dong et al., Phys. Rev. Lett. 103, 127201 (2009)], two (related) mechanisms were proposed to understand the intrinsic exchange bias present in oxides heterostructures involving G-type antiferromagnetic perovskites. The first mechanism is driven by the Dzyaloshinskii-Moriya interaction, which is a spin-orbit coupling effect. The second is induced by the ferroelectric polarization, and it is only active in heterostructures involving multiferroics. Using the SrRuO(3)/SrMnO(3) superlattice as a model system, density-functional calculations are here performed to verify the two proposals. This proof-of-principle calculation provides convincing evidence that qualitatively supports both proposals.
关键词:
thin-films;weak ferromagnetism;superlattices;anisotropy;bifeo3;srruo3;model
