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Effect of Gd content on microstructure and mechanical properties of Mg-Y-RE-Zr alloys 总被引:2,自引:2,他引:0
Four kinds of Mg-Y-RE-Zr alloys with different Gd contents were prepared,and the effect of Gd content on microstructure and mechanical properties of the alloys was researched.Based on the experimental investigation,the compounds at the grain boundaries are mainly Mg_(24)Y_5,Mg_(41)Nd_5,and Mg_5Gd phases.The average grain size of as-cast alloys is 50-60μm.After T4(535℃, 24 h)treatment,Mg_5Gd phases mostly decompose and dissolve into the matrix,and the disperse spotted phases are mainly Mg_(24)Y_5 and Mg_(... 相似文献
84.
Three kinds of autotrophic bioleaching bacteria strains, including mesophilic and acidophilic ferrous ion-oxidizing bacteria Acidithiobacillus ferrooxidans (A. ferrooxidans), mesophilic and acidophilic sulfur-oxidizing bacteria Acidithiobacillus thiooxidans (A. thiooxidans), and moderately thermophilic sulfur-oxidizing bacteria Acidianus brierleyi, were cryopreserved in liquid nitrogen and their ferrous ion- or sulfur-oxidizing activities were investigated and compared with the original ones. The results revealed that ferrous ion/sulfur oxidation activities of the strains were almost equal before and after cryopreservation. Glycerin was used as cryoprotective agent. In conclusion, liquid-nitrogen cryopreservation is a simple and effective method for autotrophic bioleaching microorganisms. 相似文献
85.
The effect of Cu~(2+)ions on bioleaching of marmatite was investigated through shake leaching experiments.The bacteria inoculated are a mixed culture ofAcidithiobacillus ferrooxidans,Acidithiobacillus thiooxidans and Lepthospirillum ferrooxidans.The results show that zinc is selectively leached,and the addition of appropriate content of Cu~(2+)ions has positive effect on the bioleaching of marmatite.SEM and EDX analyses of the leaching residue reveal that a product layer composed of iron sulfide, element... 相似文献
86.
In situ TiB2 reinforced 6351 Al alloy composites were subjected to compression testing at strain rates and temperatures ranging from 0.001 to 10 s -1 and from 300 to 550℃,respectively,using Gleeble-1500D system.And the associated microstructural transformations and instability phenomena were studied by observations of the optical and transmission electron microscope.The power dissipation efficiency and instability parameter were calculated following the dynamic material model and plotted with the temperatur... 相似文献
87.
A new strain named YTW315 was isolated from Dexing area using the double-layer culture technique. The morphological, biochemical and physiological characteristics of YTW315 were studied. Physiological investigation indicates that the strain YTW315 is a strict (obligate) chemolithoautotroph, metabolizing ferrous iron and pyrite. The optimal growth conditions for the strain are 40 ℃ and pH 1.6. A phylogenetic analysis based on 16S rRNA sequences shows that the isolate is clustered to Leptospirillum ferriphilum with 99.8% similarity to Leptospirillum ferriphilum strain Fairview and ATCC 49881. The molar fraction of DNA (G+C) of the isolate is 58.1%. The strain can tolerate high concentration of Fe(Ⅲ) and As(V) (500 mmol/L and 50 mmol/L, respectively). Bioleaching experiment indicates that the strain can oxidize Fe(Ⅱ) efficiently, and after 30 d, 44.56% of copper and 95.31% of iron are extracted from chalcopyrite and pyrite, respectively. 相似文献
88.
Yuchang Qing Wancheng Zhou Shu Jia Fa Luo Dongmei Zhu State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi an China 《材料科学技术学报》2010,26(11):1011-1015
Microwave absorbing properties of the carbonyl iron particles filled epoxy-silicone resin coatings showed visible degression when the coatings were heat treated at 300 ℃ with different time.The complex permittivity and permeability of the coatings before and after heat treatment were measured.After heat treatment at 300 ℃,the real part of permittivity of the coatings increased with increasing treatment time and showed frequency dependence dielectric response.The complex permeability showed remarkable variat... 相似文献
89.
简要介绍了MATLAB软件及其主要特点,讨论了磁性材料的温度特性及其测量方法,重点分析了MATLAB在磁光记录薄膜温度特性研究中的应用:通过插值方法用已知实验数据点估算新的数据点,应用MATLAB数学函数求解磁光记录薄膜各功能层的居里温度。本文的具体实例表明,在磁学研究中使用MATLAB可以提高实验效率。 相似文献
90.