International Journal of Minerals, Metallurgy and Materials

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Existence and release of fluid inclusions in bornite and its associated quartz and calcite

Jiu-shuai Deng, Shu-ming Wen, Dan-dan Wu, Jian Liu, Xiao-lin Zhang, Hai-ying Shen

2013, 20(9): 815-822. doi: 10.1007/s12613-013-0801-9

中文摘要(224) PDF(8) SpringerLink

摘要:
The existence and release of fluid inclusions in bornite and its associated minerals, namely, quartz and calcite were investigated and confirmed. The structures, forms, and phases of these large quantities of fluid inclusions were also studied. A mass of fluid inclusions with various sizes, distributions, shapes, and phases exist in bornite and its associated minerals. Their sizes vary from a few micrometers to tens of micrometers, and the forms appear as negative crystals, or elongated, elliptical, and irregular. At room temperature, fluid inclusions were mainly characterized as gas-liquid twophase. However, small amounts of fluid inclusions with pure gas phase and pure liquid single-phase were also observed in quartz and calcite. These fluid inclusions initially broke during the ore crushing and grinding process and then released into the flotation pulp in the flotation process. The quantitative analysis of fluid inclusions in the solution and the comparisons of mineral dissolution show that the amount of copper and iron released by fluid inclusions in the bornite sample is higher than the amount dissolved by the mineral; fluid inclusions in the associated gangue minerals, quartz, and calcite also make contribution.

Extraction of Zr(IV) from hydrochloric acid with tri-octyl amine and Cyanex 921 in kerosene

Bhikari Charan Bhatta, Nandita Panda, Sujata Mishra

2013, 20(9): 823-828. doi: 10.1007/s12613-013-0802-8

中文摘要(312) PDF(14) SpringerLink

摘要:
This article reports the extraction of zirconium (IV) from aqueous HCl solution by tri-octyl amine (TOA), Cyanex 921, and their binary mixture using kerosene as the diluent. The effect of some parameters on the extraction of Zr(IV) was investigated such as equilibration time, aqueous phase acidity, extractant molarity, chloride ion concentration, nature of diluents, and temperature. The extraction of Zr(IV) was found to be 99% from 7.5 M HCl using the mixture of extractants containing 0.1 M TOA and 0.02 M Cyanex 921 in kerosene. Kerosene was found to be the effective diluent for the extraction of Zr(IV) with the binary mixture of TOA and Cyanex 921. The positive enthalpy change and positive entropy change in the binary extraction system show the endothermic process with an increase in entropy. Stripping of Zr(IV) from the loaded organic phase containing the mixture of TOA (0.1 M) and Cyanex 921 (0.02 M) indicates that HNO₃ and Na₂CO₃ are the best stripping agents.

High-temperature mechanical properties of near-eutectoid steel

Jun Fu, Fu-ming Wang, Fang Hao, Gui-xiang Jin

2013, 20(9): 829-834. doi: 10.1007/s12613-013-0803-7

中文摘要(304) PDF(8) SpringerLink

摘要:
The high-temperature mechanical properties of near-eutectoid steel were studied with a Gleeble-1500 simulation machine. Zero strength temperature (ZST), zero ductility temperature (ZDT), hot ductility curves, and strength curves were measured. Two brittle zones and one plastic zone were found in the temperature range from the melting point to 600℃. Embrittlement in zone I is caused by the existence of liquid film along dendritic interfaces. Ductility loss in zone III mainly results from precipitates and inclusions as well as S segregation along grain boundaries. Pearlite transformation also accounts for ductility deterioration in the temperature range of 700–600℃. Moreover, the straightening temperature of the test steel should be higher than 925℃ for avoiding the initiation and propagation of surface cracks in billets.

Effect of high temperature and high strain rate on the dynamic mechanical properties of Fe-30Mn-3Si-4Al TWIP steel

Zhi-ping Xiong, Xue-ping Ren, Wei-ping Bao, Jian Shu, Shu-xia Li, Hai-tao Qu

2013, 20(9): 835-841. doi: 10.1007/s12613-013-0804-6

中文摘要(274) PDF(9) SpringerLink

摘要:
The dynamic mechanical properties of Fe-30Mn-3Si-4Al twinning induced plasticity (TWIP) steel were studied by the split-Hopkinson pressure bar (SHPB) at temperatures of 298–1073 K and strain rates of 700, 2500, and 5000 s⁻¹. The TWIP steel indicates strain rate hardening effect between 700 and 2500 s⁻¹, but it shows strain rate softening effect between 2500 and 5000 s⁻¹. In addition, the strain rate softening effect enhances with an increase in deformation temperature. After deformation, the microstructures were studied by optical microscopy (OM). It is shown that the deformation bands become more convergence, a part of which become interwoven with an increase in strain rate, and the dynamic recovery and recrystallization are enhanced with an increase in both temperature and strain rate.

Precipitation and control of BN inclusions in 42CrMo steel and their effect on machinability

Yu-nan Wang, Yan-ping Bao, Min Wang, Le-chen Zhang

2013, 20(9): 842-849. doi: 10.1007/s12613-013-0805-5

中文摘要(234) PDF(11) SpringerLink

摘要:
The precipitation and control of boron nitrogen (BN) inclusions in 42CrMo steel were investigated and their effect on machinability was analyzed. First, the precipitation regularity of BN in 42CrMo steel was studied by theoretical calculation. Then, the machinability of the steel was investigated through contrast cutting experiments, and the composition and cooling rate of the steel were controlled to analyze the variation laws of the size, distribution, and area ratio of BN inclusions. Finally, the results were combined with the machinability of the steel to analyze the relationship among them. It is found that the machinability of the steel is mainly influenced by the diameter and quantity of BN inclusions. Fine and dispersedly distributed BN inclusions are more beneficial for the improvement in machinability of 42CrMo steel than coarse and sparse BN inclusions.

Corrosion behavior of ferritic stainless steel with 15wt% chromium for the automobile exhaust system

Hua-bing Li, Zhou-hua Jiang, Hao Feng, Hong-chun Zhu, Bin-han Sun, Zhen Li

2013, 20(9): 850-860. doi: 10.1007/s12613-013-0806-4

中文摘要(288) PDF(8) SpringerLink

摘要:
The effect of chloride ion concentration, pH value, and grain size on the pitting corrosion resistance of a new ferritic stainless steel with 15wt% Cr was investigated using the anodic polarization method. The semiconducting properties of passive films with different chloride ion concentrations were performed using capacitance measurement and Mott-Schottky analysis methods. The aging precipitation and intergranular corrosion behavior were evaluated at 400–900℃. It is found that the pitting potential decreases when the grain size increases. With the increase in chloride ion concentration, the doping density and the flat-bland potential increase but the thickness of the space charge layer decreases. The pitting corrosion resistance increases rapidly with the decrease in pH value. Precipitants is identified as Nb(C,N) and NbC, rather than Cr-carbide. The intergranular corrosion is attributed to the synergistic effects of Nb(C,N) and NbC precipitates and Cr segregation adjacent to the precipitates.

Coarsening behavior of γ′ and γ″ phases in GH4169 superalloy by electric field treatment

Lei Wang, Yao Wang, Yang Liu, Xiu Song, Xu-dong Lü, Bei-jiang Zhang

2013, 20(9): 861-866. doi: 10.1007/s12613-013-0807-3

中文摘要(298) PDF(15) SpringerLink

摘要:
The coarsening behaviors of γ′ and γ″ phases in GH4169 alloy aged at 1023 and 1073 K with electric field treatment (EFT) were investigated by transmission electron microscopy (TEM) and positron annihilation lifetime spectroscopy (PALS). It is demonstrated that precipitation coarsening occurs, and the growth activation energies of γ′ and γ″ phases can be decreased to 115.6 and 198.1 kJ·mol⁻¹, respectively, by applying the electric field. The formation of a large number of vacancies in the matrix is induced by EFT. Due to the occurrence of vacancy migration, the diffusion coefficients of Al and Nb atoms are increased to be 1.6–5.0 times larger than those without EFT at 1023 or 1073 K. Furthermore, the formation of vacancy clusters is promoted by EFT, and the increase in strain energy for the coarsening of γ′ and γ″ phases can be counterbalanced by the formation of vacancy clusters.

Martensitic transformation and magnetic properties of aged Ni-Fe-Ga-Ti shape memory alloy

Nader El-Bagoury, Mahmoud Mohamed Hessien, Magdy Abdel Wahab Kaseem

2013, 20(9): 867-873. doi: 10.1007/s12613-013-0808-2

中文摘要(321) PDF(7) SpringerLink

摘要:
This article reports the effect of ageing on the microstructure, martensitic transformation, magnetic properties, and mechanical properties of Ni₅₁Fe₁₈Ga₂₇Ti₄ shape memory alloy. There are five specimens of this alloy aged at 573 up to 973 K for 3 h per each. This range of ageing temperature greatly affects the microstructure of the alloy. As the ageing temperature increased from 573 up to 973 K, the microstructure of Ni₅₁Fe₁₈Ga₂₇Ti₄ alloy gradually changed from the entirely martensitic matrix at 573 K to the fully austenitic microstructure at 973 K. The volume fraction of precipitated Ni₃Ti particles increased with the ageing temperature increasing from 573 to 773 K. Further increasing the ageing temperature to 973 K decreased the content of Ni₃Ti in the microstructure. The martensitic transformation temperature was decreased steadily by increasing the ageing temperature. The magnetization saturation, remnant magnetization, and coercivity increased with the ageing temperature increasing up to 773 K. A further increase in ageing temperature decreased these magnetic properties. Moreover, the hardness values were gradually increased at first by increasing the ageing temperature to 773 K, and then dramatically decreased to the lowest value at 973 K.

Matched glass-to-Kovar seals in N₂ and Ar atmospheres

Cheng-hsien Kuo, Pi-ying Cheng, Chang-pin Chou

2013, 20(9): 874-882. doi: 10.1007/s12613-013-0809-1

中文摘要(303) PDF(16) SpringerLink

摘要:
The oxidation of Kovar alloy was investigated, the wetting and spreading behavior of hard and soft glasses on Kovar alloy were studed by using the sessile drop method, and the quality and the seal strength of glass-Kovar seals were tested. The experimental results indicated that the preoxidation of Kovar alloy for approximately 10 min at 700℃ in air resulted in excellent adherence in glass-Kovar seals. The wetting and spreading behavior of glass on preoxidized Kovar alloy were superior to that on nonoxidized Kovar alloy. The wetting ability of ASF110 glass, at 950℃ and 980℃ in Ar and N₂ atmospheres, was significantly superior to that of ASF200R and ASF700 glasses. The seal quality of the glass-preoxidized Kovar seal was superior to that of the glass-nonoxidized Kovar seal. The shear strength of the ASF110 glass-preoxidized Kovar seal, which was prepared at 980℃ for 20 min in an Ar atmosphere, was approximately 3.9 MPa.

Interfacial intermetallic compound growth and shear strength of low-silver SnAgCuBiNi/Cu lead-free solder joints

Guo-qiang Wei, Lei Wang, Xin-qiang Peng, Ming-yang Xue

2013, 20(9): 883-889. doi: 10.1007/s12613-013-0810-8

中文摘要(295) PDF(8) SpringerLink

摘要:
The growth rule of the interfacial intermetallic compound (IMC) and the degradation of shear strength of Sn-0.8Ag-0.5Cu-2.0Bi-0.05Ni (SACBN)/Cu solder joints were investigated in comparison with Sn-3.0Ag-0.5Cu (SAC305)/Cu solder joints aging at 373, 403, and 438 K. The results show that (Cu_1−x,Ni_x)₆Sn₅ phase forms between the SACBN solder and Cu substrate during soldering. The interfacial IMC thickens constantly with the aging time increasing, and the higher the aging temperature, the faster the IMC layer grows. Compared with the SAC305/Cu couple, the SACBN/Cu couple exhibits a lower layer growth coefficient. The activation energies of IMC growth for SACBN/Cu and SAC305/Cu couples are 111.70 and 82.35 kJ/mol, respectively. In general, the shear strength of aged solder joints declines continuously. However, SACBN/Cu solder joints exhibit a better shear strength than SAC305/Cu solder joints.

Influence of Ce and Mn addition on α-Fe morphology in recycled Al-Si alloy ingots

Chao Fan, Si-yuan Long, Huai-de Yang, Xiang-jie Wang, Jun-cheng Zhang

2013, 20(9): 890-895. doi: 10.1007/s12613-013-0811-7

中文摘要(303) PDF(22) SpringerLink

摘要:
The influence of Ce or Ce and Mn combined additions on the morphology of α-Fe phases in recycled Al-Si alloys was experimentally investigated by microstructure observation and room temperature tensile testing. It is found that Ce modifies the morphology of α-Fe phase from the large Chinese script-like into the individual and fine nodular shape. A combined addition of Ce and Mn results in the promotion of primary α-Fe formation, and their size increases considerably with the increase in Ce content. The mechanism of the above morphological changes was discussed in accordance with the nucleation and growth of α-Fe phase during solidification.

Microstructure and mechanical properties of AZ91 magnesium alloy subject to deep cryogenic treatments

Gui-rong Li, Hong-ming Wang, Yun Cai, Yu-tao Zhao, Jun-jie Wang, Simon P. A. Gill

2013, 20(9): 896-901. doi: 10.1007/s12613-013-0812-6

中文摘要(442) PDF(14) SpringerLink

摘要:
AZ91 magnesium alloy was subjected to a deep cryogenic treatment. X-ray diffraction (XRD), scanning electronic microscopy (SEM), and transmission electronic microscopy (TEM) methods were utilized to characterize the composition and microstructure of the treated samples. The results show that after two cryogenic treatments, the quantity of the precipitate hardening β phase increases, and the sizes of the precipitates are refined from 8–10 μm to 2–4 μm. This is expected to be due to the decreased solubility of aluminum in the matrix at low temperature and the significant plastic deformation owing to internal differences in thermal contraction between phases and grains. The polycrystalline matrix is also noticeably refined, with the sizes of the subsequent nanocrystalline grains in the range of 50–100 nm. High density dislocations are observed to pile up at the grain boundaries, inducing the dynamic recrystallization of the microstructure, leading to the generation of a nanocrystalline grain structure. After two deep cryogenic treatments, the tensile strength and elongation are found to be substantially increased, rising from 243 MPa and 4.4% of as-cast state to 299 MPa and 5.1%.

Modulation of active Cr(III) complexes by bath preparation to adjust Cr(III) electrodeposition

Lei Li, Zhi Wang, Ming-yong Wang, Yi Zhang

2013, 20(9): 902-908. doi: 10.1007/s12613-013-0813-5

中文摘要(287) PDF(9) SpringerLink

摘要:
The preparation process of the Cr(III) bath was studied based on a perspective of accelerating the formation of active Cr(III) complexes. The results of ultraviolet-visible absorption spectroscopy (UV-Vis) and electrodeposition showed that active Cr(III) complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr(III) complexes. The chromium deposition rate increased with the concentration of active Cr(III) complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71 μm/min. When the concentration of active Cr(III) complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr(H₂O)₄(OH)L²⁺ (L is an organic ligand, and its valence is omitted) is a primary active Cr(III) complex.

Electrodeposition of aluminium and aluminium-copper alloys from a room temperature ionic liquid electrolyte containing aluminium chloride and triethylamine hydrochloride

P. V. Suneesh, T. G. Satheesh Babu, T. Ramachandran

2013, 20(9): 909-916. doi: 10.1007/s12613-013-0814-4

中文摘要(322) PDF(14) SpringerLink

摘要:
The electrodeposition of Al and Al-Cu binary alloys on to gold substrates from a room temperature ionic liquid electrolyte containing AlCl₃-Et₃NHCl was studied. The electrochemical behavior of the electrolyte and the mechanism of deposition were investigated through cyclic voltammetry (CV), and the properties of deposits obtained were assessed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD). Al of 70 μm in thickness and an Al-Cu alloy of 30 μm in thickness with 8at% copper were deposited from the electrolyte. SEM images of the deposits indicate that the Al deposit was smooth and uniform, whereas the Al-Cu deposit was nodular. The average crystalline size, as determined by XRD patterns, was found to be (30 ± 5) and (29 ± 5) nm, respectively, for Al and Al-Cu alloys. Potentiodynamic polarization (Tafel plots) and electrochemical impedance spectroscopic (EIS) measurements showed that Al-Cu alloys are more corrosion resistant than Al.

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2013年第20卷第9期