材料期刊网

Microstructure, Mechanical Properties, Corrosion Behavior and Biocompatibility of As-Extruded Biodegradable Mg-3Sn-1Zn-0.5Mn Alloy

Hou Lida , Li Zhen , Zhao Hong , Pan Yu , Pavlinich Sergey , Liu Xiwei , Li Xinlin , Zheng Yufeng , Li Li

材料科学技术（英） doi:10.1016/j.jmst.2016.07.004

The microstructure evolution and mechanical properties of biodegradable Mg-3Sn-1Zn-0.5Mn alloys were investigated by the optical microscopy, X-ray diffractometer and a universal material testing machine. The corrosion and degradation behaviors were studied by potentiodynamic polarization method and immersion test in a simulated body fluid (SBF). It was found that the as-extruded Mg-3Sn-1Zn-0.5Mn alloy has the fine equiaxed grains which underwent complete dynamic recrystallization during the hot extrusion process, with the second phase particles of Mg₂Sn precipitated on the grain boundaries and inside the grains. The tensile strength and elongation of as-extruded Mg-3Sn-1Zn-0.5Mn alloys were 244?±?3.7?MPa and 19.3%?±?1.7%, respectively. The potentiodynamic polarization curves in SBF solution indicated the better corrosion resistance of the as-extruded Mg-3Sn-1Zn-0.5Mn alloy in the SBF solution. Immersion test in the SBF solution for 720?h revealed that the corrosion rate of as-extruded Mg-3Sn-1Zn-0.5Mn alloy was nearly 4?±?0.33?mm/year. The hemolysis rate of as-extruded Mg-3Sn-1Zn-0.5Mn alloy was lower than the safe value of 5% according to ISO 10993-4. As-extruded Mg-3Sn-1Zn-0.5Mn alloy showed good biocompatibility after being implanted into the dorsal muscle and the femoral shaft of the rabbit, and no abnormalities were found after short-term implantation. It was revealed that the as-extruded Mg-3Sn-1Zn-0.5Mn alloy is a promising material for biodegradable implants, which possesses an interesting combination of preferred mechanical properties, better corrosion resistance and biocompatibility.

关键词: Biodegradable magnesium alloy , Extrusion , Mechanical property , Corrosion , Biocompatibility

Reply to Comments on "Interdiffusion in the beta phase region of the Ni-Al-Cr system"

Scripta Materialia

A recent comment on a previously published paper addressed the invalid explanation of the off diagonal interdiflusion coefficients of the beta-Ni(Al,Cr) phase in the Ni-Cr-Al system according to the symmetric property of the thermodynamic matrix. In this paper, the experimental data presented by Hou et al. was reanalyzed and the interdiffusion coefficient matrix was estimated again. The results of the analysis have been discussed in terms of a brief reply to the comments of Liu and Liang. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

关键词: Diffusion;Intermetallic compound;Ni-Cr-Al

制冷剂过热气体热力性质的隐式拟合方法

张春路 , 丁国良 , 李灏

工程热物理学报

准确、快速、稳定地计算制冷剂热力性质是计算机辅助设计和工程计算的 要求。本文将隐式拟合方法与MartinHou方程相结合，提出制冷剂过热气体热力 性质的隐式拟合方法，该方法不仅具有形式统一、精度高、速度快、外推性和 稳定性好的优点，而且保证了过热区与两相区之间热力性质的连续性

关键词: 制冷剂 , 过热气体 , 热力性质 , 拟合

缝合复合材料低速冲击损伤研究

曾东 , 燕瑛 , 王立朋 , 刘兵山

复合材料学报 doi:10.3321/j.issn:1000-3851.2005.06.022

通过三维动力学有限元法,采用空间杆单元来描述缝线,结合试验系统地研究了缝合复合材料的低速冲击损伤问题.采用修正的赫兹接触定律计算冲击接触力,NewMark直接积分法求解运动方程,求解冲击过程中的应力应变;在Chang和Hou等的分层扩展准则基础上,提出一修正的分层扩展准则并考虑纤维断裂,建立了分析低速冲击损伤面积的方法;对相同铺层的缝合与未缝合复合材料层板进行了低速冲击试验.分析结果与实验结果具有良好的一致性,证明本文中提出的修正的分层扩展准则是正确的.计算及试验结果均表明,在相同冲击能量作用下,缝合使冲击损伤面积明显减小.

关键词: 缝合复合材料 , 低速冲击 , 三维有限元 , 损伤面积

Ab initio calculations of the electronic structure of the silver palladium oxide Ag2PdO2

Physica B-Condensed Matter

Ab initio calculations of the electronic structure were performed for the silver palladium oxide, Ag2PdO2 by the full potential mixed linearized augmented plane wave and augmented plane wave plus local orbitals method (mixed LAPW/APW + lo) within the density functional theory and using the generalized gradient approximation (GGA96, Phys. Rev. Lett. 77 (1996) 3865) for the exchange-correlation potential. The lattice parameters were calculated from the ground-state total energy versus volume curve, and are in good agreement with the available experimental results. Our calculations of band structure predicted that the compound Ag2PdO2 has indirect band gap, and the Pd 4d states strongly hybridize with the O 2p states all over the valence bands and conduction bands. The valence bands are composed mainly of Ag, Pd 4d states and 0 2p states, while the conduction bands consist mainly of the Pd 4d states and 0 2p states. In addition, focusing on the calculation precision of the band gap, three different kinds of basis sets ("pure" LAPW, APW + lo and mixed LAPW/APW + lo) and three versions of exchange-correlation potential (GGA96, Phys. Rev. Lett. 77 (1996) 3865; LIDA, Phys. Rev. B 45 (1992) 13244; GGA91, Phys. Rev. B 46 (1992) 6671; Ziesche and Eschrig (Eds.), Electronic Structure of Solids '91, Akademie Verlag, Berlin, 199 1, p. 11) were chosen to calculate the band structure, the results show that the three basis sets lead to almost the same band gap values. (C) 2003 Elsevier B.V. All rights reserved.

关键词: silver palladium oxide;ab initio calculation;mixed LAPW/APW plus lo;method;band structure;band gap;generalized gradient approximation;plane-wave method;crystal-structure;band-structure;phase-diagram;system;copper;energy;solids