查看更多>>摘要：The Transactions of Nonferrous Metals Society of China(hereafter Trans. Nonferrous Met. Soc. China), founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published bimonthly and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on materials science and engineering. It is the unique preeminent publication in English of The Nonferrous Metals Society of China for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, INSPEC, CA, METADEX, AJ, JICST.
查看更多>>摘要：Influences of the three melt treatment processes (namely, refinement with carbon inoculation, electromagnetic stirring and "refinement & electromagnetic stirring" processing) on the microstructures of AZ91D alloy were explored experimentally. The results indicate that the micron carbon powders inoculation processing with 0.1% (mass fraction) addition level makes the grain size of the primary phase (α-Mg) decrease to approximate 40% that of the initial primary crystal, from about 530μm to 200 μm around. The electromagnetic stirring processing not only decreases the grain sizes sharply, but also transfers the grain shape of α-Mg from coarse dendritic to nearly spheralitic with the shape factor from about 0.1 to approximate 0.8. And the "refinement & electromagnetic stirring" processing improves grain shape of α-Mg further and refines grain size to about 72 μm, less than 15% that of the initial primary crystal.
查看更多>>摘要：The effect of the liquid-liquid structure transition(L-LST) on the solidification behaviors and morphologies of Sn-Bi alloys was studied further. The results show that the undercooling of the primary and eutectic phase increases and the microstructure becomes finer after solidifying from the melt experiencing the L-LST. In the meantime, in hypoeutectic alloy, when solidifying from the melt experiencing the L-LST, the morphology of primary phase changes from the fir-tree crystal into the equiaxed crystal, and less primary phase and more eutectic structure are observed. Moreover, in eutectic alloy, the spacing of eutectic phase decreases markedly. These investigations would be beneficial to further exploration of the correlation between the melt structure and the micro mechanism of solidification.
查看更多>>摘要：The nanocrystalline Al-Zn-Mg-Cu alloy powders were synthesized using cryomilling. Deformation twins and twinning at ambient temperature were observed in Al-Zn-Mg-Cu powders. Experimental results indicate that high strain rate at low temperature during cryomilling induces the formation of deformation twins by the climbing of the restricted dislocations in nano-scale grains, and the cryomilled powders at high energies and nonequilibrium state reduce the grain boundary energies by twinning.
查看更多>>摘要：Fenton's oxidation method was successfully used to synthesize an ideal titania film in situ on NiTi shape memory alloy(SMA) for medical applications. Characterized with scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, inductively coupled plasma mass spectrometry and electrochemical tests, it is found that the titania film produced by Fenton's oxidation method on NiTi SMA is nanostructured and has a Ni-free zone near its top surface, which results in a notable improvement in corrosion resistance and a remarkable decrease in leaching of harmful Ni ions from NiTi SMA in simulated body fluids. The improvement of effectiveness to corrosion resistance and the reduction in Ni release of NiTi SMA by Fenton's oxidation method are comparable to those by oxygen plasma immersion ion implantation reported earlier.
查看更多>>摘要：The effect of partial substitution of Al for Cu on the glass forming ability(GFA) and mechanical properties of Mg_(65)Cu_(25-x)Al_xGd_(10)(x=0, 1, 3 and 5, molar fraction, %) alloys were studied by X-ray diffractometry(XRD), differential scanning calorimetry(DSC) and uniaxial compression test. The result reveals that GFA of the alloys changes slightly with increasing x from 0 to 3, and then abruptly decreases with x increasing up to 5. The plasticity can be greatly improved with appropriate substitution of Cu by Al (3%, molar fraction) in Mg_(65)Cu_(25)Gd_(10) bulk metallic glass, and the resultant fracture strength, total strain to failure, and plastic strain are 898 MPa, 2.19% and 0.2%, respectively.
查看更多>>摘要：The forming limits of nickel coating on the right region were studied, so as to direct the preparation of the material and help the production of workpieces. The electrodeposited nickel coating was prepared on steel substrate to form advanced structures, and its plastic instability was investigated by the Swift Plastic Instability Theory. By using the compound law for laminated sheet metals, explicit equations for the calculation of the instable eigen values were deduced. The forming limit diagrams of the nickel coating on the right region were plotted. It is exhibited that the forming limit of the coating sheet is between the forming limits of the individual nickel coating and steel substrate. The forming limit of the nickel coating is not so good as that of the steel substrate, and the forming limit strain of the coating sheet tends to diminish with the increase of thickness of the coating. The greater the normal anisotropic coefficient of the materials is, the better the forming limit is.
查看更多>>摘要：Three nanocrystalline alloys, Fe_(50)Al_(50), Fe_(42.5)Al_(42.5)Ti_5B_(10) and Fe_(35)Al_(35)Ti_(10)B_(20) (molar fraction, %), were synthesized from elemental powders by high-energy ball milling. The structural evolutions and morphological changes of the milled powders were characterized by X-ray diffractometry(XRD), transmission electron microscopy(TEM) and scanning electron microscopy(SEM). The effects of different Ti, B additions on the structure and phase transformation in these alloys were also discussed. It is observed that the diffusion of Al, Ti, B atoms into Fe lattice occurs during milling, leading to the formation of a BCC phase identified as Fe(Al) or Fe(Al, Ti, B) supersaturated solid solution. Fe-based solid solution with nanocrystalline structure is observed to be present as the only phase in all the alloy compositions after milling. Furthermore, the contents of Ti, B affect the formation of mechanical alloying products, changes in the lattice parameter as well as the grain size.
查看更多>>摘要：Ni-6.0%SiC (mass fraction) nanocomposite coating was prepared from a nickel sulfate bath by co-electrodeposition of Ni and SiC nanoparticles in an average size of 30 nm. The oxidation at 1 000℃ shows that the Ni-6.0%SiC nanocomposite coating has a superior oxidation resistance compared with the pure Ni film due to the formation of SiO_2 oxide particles along grain boundaries, blocking the outward diffusion of Ni and changing the oxidation growth mechanism. The effect of SiC nanoparticles on the oxidation progress was discussed in detail.
查看更多>>摘要：Zr_(49)Cu_(46)Al_5 and Zr_(48.5)Cu_(46.5)Al_5 bulk metallic glasses(BMGs) with diameter of 5 mm were prepared through water-cooled copper mold casting. The phase structures of the two alloys were identified by X-ray difrractometry(XRD). The thermal stability was examined by differential scanning calorimetry(DSC). Zr_(49)Cu_(46)Al_5 alloy shows a glass transition temperature, T_g, of about 689 K, an crystallization temperature, T_x, of about 736 K. The Zr_(48.5)Cu_(46.5)Al_5 alloy shows no obvious exothermic peak. The microstructure of the as-cast alloys was analyzed by transmission electron microscopy(TEM). The aggregations of CuZr and CuZr_2 nanocrystals with grain size of about 20 nm are observed in Zr_(49)Cu_(46)Al_5 nanocrystalline composite, while the Zr_(49)Cu_(46.5)Al_5 alloy containing many CuZr martensite plates is crystallized seriously. Mechanical properties of bulk Zr_(49)Cu_(46)Al_5 nanocrystalline composite and Zr_(48.5)Cu_(46.5)Al_5 alloy measured by compression tests at room temperature show that the work hardening ability of Zr_(48.5)Cu_(46.5)Al_5 alloy is larger than that of Zr_(49)Cu_(46)Al_5 alloy.
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