Mechanical and metallurgical properties of friction stir welded dissimilar joints of AZ91 magnesium alloy and AA 6082-T6 aluminium alloy

In the present research work,AZ91 magnesium alloy and AA6082-T6 aluminium alloy were joined by friction stir welding process.The comparison of microstructure and mechanical properties between different joints by varying the different materials on advance and retreating sides were mainly studied.Four different welds have been prepared to find the material mixing between the similar and dissimilar joints.The joint interfaces of the welds have been investigated by employing an optical microscope and scanning electron microscope.When Mg was placed on advancing side(AS),more aluminium content was soluble in nugget zone than the case where Mg was placed on the retreating side(RS).Thin intermetallic layer in the joint interface of Mg/Al and thick intermetallic layer with poor adhesion of the aluminium and magnesium have been observed in the dissimilar joints varying the sides.The highest UTS of 172.3 MPa was found for Mg-Al when Mg was placed on AS and lower UTS of 156.25 MPa was obtained when Mg was placed on RS.Hardness of 86 Hv and 89 Hv were observed in the Stir zone for the dissimilar AZ91 Mg alloy and AA6082-T6 Al alloy when AZ91Mg alloy was placed on the AS and on the RS respectively.Fractography was also carried out to find the mode of failure.

Aluminium-magnesium silicate inhibits parvovirus and cures infected dogs

Ability of a synthetic Aluminium-Magnesium Silicate [AMS] to inhibit activities of canine parvovirus [CPV] was investigated in vitro and in vivo. Five samples of CPV isolated in Nigeria, were each incubated with equal amount of a synthetic AMS on a volume to weight [v/w] basis, for one hour and then centrifuged. Viral titres of the supernatants were tested by the haemagglutination [HA] test and their mean titre compared with mean titre of portions of same viral samples, not incubated with the AMS. Also, five puppies and five adult dogs infected with the parvovirus isolates were treated by dosing each with 400 mg/kg of a drug formulation that has 12% AMS per os for seven days. As control, five puppies and five adult dogs from same class as the experimental dogs were similarly infected but were not treated. Incubating parvovirus with AMS reduced its load from mean HA titre 825.6 ± 261.1 to mean HA, 270.8 ± 132.1 [p < 0.05]. Also treating parvovirus infected dogs with a 12% AMS drug formulation reduced mortality due to the virus from 100% to zero [p < 0.01].

Characteristics of Magnesium-iron-aluminium Composite Oxides and Their Influence on Properties of Magnesia-based Bricks

The composition,structure and micro-morphology of magnesium- iron- aluminum composite oxides were investigated using various methods such as XRF,SEM,EDS,XRD and KMn O4-titration. Compared to hercynite,the composite oxides have completely different phases including solid solution（ Mg O）0. 77（ Fe O）0. 23,composite spinel Mg Fe0. 2Al1. 8O4 and a small amount of Mg Fe2O4. The composite oxides exhibit excellent corrosion resistance to cement clinker and potassium salts.The products produced by magnesite and the composite oxides show better performance than magnesia- hercynite bricks,especially the corrosion resistance and thermal shock resistance.

Electrochemical corrosion behaviour of stir zone of friction stir welded dissimilar joints of AA6061 aluminium-AZ31B magnesium alloys

Joining of dissimilar metals will offer many advantages in transportation sectors such as fuel consumption,weightreduction and emission reduction.However,joining of aluminium(Al)alloys with magnesium(Mg)alloys by fusion welding processis very complicated.Friction stir welding(FSW)is a feasible method to join these two dissimilar alloys.Mixing these two metalstogether in stir zone(SZ)leads to poor corrosion resistance.In this investigation,an attempt has been made to understand thecorrosion resistance of SZ of FSWed dissimilar joints of AA6061Al alloy and AZ31B Mg alloy.Potentiodynamic polarization testwas conducted by varying chloride ion concentration,pH value of the NaCl solution and exposure time.The corroded surfaces wereanalyzed using optical microscopy,scanning electron microscopy and XRD techniques.Of these three factors investigated,exposuretime is found to be the most significant factor to influence the corrosion behaviour of SZ of friction stir welded dissimilar joints ofAl/Mg alloys.

Formation mechanism of an aluminium-based chemical conversion coating on AZ91D magnesium alloy

An environmentally clean aluminium-based conversion coating on AZ91D magnesium alloy was studied in aluminium nitrate solutions. The morphology, composition, structure, and formation mechanism of the coating were investigated in detail using scanning electron microscopy/energy dispersion spectrometry, X-ray diffraction, transmission electron microscopy, and electrochemical corrosion tests. The results show that the conversion coating is composed of magnesium, aluminium, and oxygen, and shows an amorphous structure. In the initial stage of coating formation, the grain-like nucleus is composed of Al10O15·xH2O, （Al2O3）5.333, Al2O3, AlO（OH）, MgAl2O4, （Mg0.88Al0.12）（Al0.94Mg0.06）2O4, and （Mg0.68Al0.32）（Al0.84Mg0.16）2O4. The conversion coating formed in the 0.01 mol/L aluminium nitrate solution for 15 min can improve the corrosion resistance of the magnesium alloy greatly. The discussion reveals that the possible formation mechanism for the aluminium-based conversion coating is the reduction reaction on micro-cathodic sites due to the electrochemically heterogeneous magnesium alloy substrate.

The Adsorption of NO_X on Magnesium Aluminium Hydrotalcite

Magnesium aluminium hydrotalcite (Mg-Al-HT) with molar ratio of Mg-to-Al of 3 to l was prepared and characterized by X-ray diffraction (XRD) and infrared spectra (IR). The performances of Mg-Al-HT for the adsorption and desorption of NOx were studied. The results indicated that the adsorption capacity of the hydrotalcite for NOx was 1398.2 mg/g, and it was higher than the acticarbon's. The adsorption capacities depended on adsorption time and temperature. Mg-Al-HT could be regenerated by thermal decomposition, and the adsorption efficiency had not changed markedly after three cycles.

Adjuvant effect of a synthetic Aluminium-Magnesium Silicate on chloroquine phosphate, against Plasmodium berghei

Effect a synthetic Aluminium-Magnesium Silicate (AMS) has on chloroquine was tested. Thirty, Plasmodium berghei-infected mice, in three experimental groups (7 mg/kg, 5 mg/kg and 3 mg/kg) of 10 mice each, were treated. Two subgroups, in each experiment, were treated with chloroquine and with a chloroquine-AMS drug formulation, respectively. Five of the infected mice served as controls. Parasitaemia (%), Haemoglobin concentration (Hb), Red Blood Cells (RBC), rectal temperature and body weight were assessed. Parasitaemia of subgroups treated at 7 mg/kg were higher than that of the control. Also, at 7 mg/kg, there was mortality with chloroquine (20%) and with the chloroquine-AMS drug (80%). At 5 mg/kg and 3 mg/kg, the AMS significantly (P < 0.05) improved ability of chloroquine to reduce plamodial parasitaemia, from 2.46 ± 0.21 to 1.57 ± 0.25 and from 3.82 ± 0.06 to 2.12 ± 0.08. It also significantly (P < 0.05) improved means of Hb and RBC from 12.25 ± 0.27 and 88.99 ± 5.72 to 12.68 ± 0.18 and 92.91 ± 4.01 and from 10.18 ± 3.00 and 63.39 ± 18.02 to 12.98 ± 0.47 and 95.23 ± 5.32. Body weight increased at 5 mg/kg, from 29.06 ± 1.95 to 32.66 ± 2.10 kg (P < 0.05) while at 3 mg/kg, rectal temperature reduced from 37.35 ± 0.32 to 36.84oC ± 0.23oC (P < 0.05). These results suggest, AMS worsened chloroquine toxicity at 7 mg/kg but potentiated its antiplasmodial activities at the lower doses.

Effective treatment of resistant <i>Escherichia coli</i>infection, with sulphadimidine stabilized in a synthetic Aluminium-Magnesium Silicate

To investigate if Aluminium-Magnesium Silicate (AMS) could make drugs regain effects against resistant pathogens, its effect was tested on sulphadimidine against sulphadimidine-resistant Escherichia coli. Two groups of chicks infected with sulphadimidine-resistant E. coli were treated at sulphadimidine dose rate of 1 g/litre of drinking water, with sulphadimidine and with an AMS-sulphadimidine drug formulation, respectively. Two other groups were similarly treated at sulphadimidine dose rate of 0.75 g/litre, while the fifth group served as control. Mean titres of the bacterium in bile of the chicks were compared. Titres, 119,200 ± 55,800 CFU/mL of the group treated with sulphadimidine at rate of 1 g/ litre and 14,800 ± 1700 CFU/mL of the group treated at rate of 0.75 g/litre, did not vary from 33,200 ± 5200 CFU/mL of the control (P > 0.05) but 295,200 ± 106,400 CFU/ml of the group treated at rate of 1 g/litre, with the AMS-sulpha- dimidine drug was significantly (P < 0.05) higher than that of the control while 5200 ± 1400 CFU/mL of the group treated at dose of 0.75 g/litre, with the AMS-sulphadimidine drug, reduced significantly (P < 0.05).

Corrosion behaviour of aluminium magnesium alloys in molten sodium

The corrosion behaviour of the Al 1%Mg, Al 3%Mg, Al 5%Mg and Al 3%Mg 0.15%Zr alloys in molten sodium was investigated. The morphology of the corrosion products and the alloying element distribution of the specimens were analyzed by using OM, SEM and EDS. The results showed that the effects of the magnesium content and the immersion temperature on the corrosion of the specimens are related to β phase (Mg 5Al 8).

Antiviral effects of a synthetic Aluminium-Magnesium Silicate, on Avian Influenza Virus

Effects a synthetic Aluminium-Magnesium Silicate [AMS] has on Avian Influenza Virus (AIV) were tested. Equal amounts of AIV samples and of the AMS were mixed, kept one hour at room temperature before centrifuging. The supernatants were remeasured and tested for, viral titre, Mean Death Time (MDT) and Mortality Rate of chicken Embryos (EMR). Volumes of the viral samples reduced at rate of 23.4% ± 5.48%. Viral titres reduced significantly (P < 0.01) from HA, 73 ± 32.72 to 1.4 ± 0.43. Also, EMR of infected chicken embryos reduced from 100% to 65%, while MDT of those that died,increased significantly (P < 0.01) from 76 ± 4.38 to 136 ±18.93 hours. When incubation with AMS was repeated on portions of an AIV sample, MDT increased from 64 to 104 hours with the portion incubated once. AIV portions on which incubation with AMS was repeated could not kill chicken embryos.

Antibacterial activity of Ampicillin trihydrate formulated in Aluminium-Magnesium Silicate, against <i>Salmonella gallinarum</i>

To test if stabilizing Ampicillin trihydrate (AT) with Aluminium-Magnesium Silicate (AMS) can enhance its antibacterial activities, different concentrations of AT solution and of a formulation of AT in the AMS, were made and used for sensitivity test on Salmonella gallinarum cultures. Also, S. gallinarum-infected chicks were treated with;10 mg/Kg (AT), 10 mg/Kg (AT in AMS), 7.5 mg/Kg (AT), 7.5 mg/Kg (AT in AMS). Mean diameter of inhibition zone, 28.39 ± 2.07 mm produced by AT did not vary significantly (P > 0.05) from 26.36 ± 2.05 mm produced by AT in AMS. However, mean Salmonella gallinarum culture forming units per ml of bile, 17.6 ± 11 × 105of the untreated chicks and 3.4 ± 0.81 × 105(80.58% reduction), 2.4 ± 0.67 × 105(85.70% reduction), 5.4 ± 1.93 × 105(69.20% reduction ) and 0.38 ± 0.13 × 105(97.80% reduction ) of the respective treated groups, showed AMS significantly (P S. gallinarum infection, in vivo.

Efficacy of piperzine citrate, stabilized with Aluminium-Magnesium Silicate, against <i>Helignosomoides bakeri</i>

To test effect of a synthetic Aluminium-Magnesium Silicate (AMS) on anthelmintic efficacy of piperazine citrate (PC), 35 mice were infected by dosing each, 0.15 ml Helignosomoides bakeri sample which contained 200 infective larvae, per os. Following comfirmation of establishment of infection by faecal floatation, they were assigned into seven groups of 5 each, and were treated with piperazine citrate, per os, at rates of 110 mg/kg (PC), 110 mg/kg (PC in AMS), 82.5 mg/kg (PC), 82.5 mg/kg (PC in AMS), 55 mg/kg (PC) and 55 mg/kg (PC in AMS) respectively. The seventh group served as untreated control. Mean Eggs Per Gramm of faeces (EPG) were 375 ± 32.27, 175 ± 14.43, 830 ± 1.04, 70 ± 12.25, 850 ± 293.06, 370 ± 58.54 and 2,200 ± 2.55 respectively. This showed EPG reduction rates of 83%, 92%, 62%, 97%, 61% and 83% among the respective treated groups.

Microstructure and mechanical properties of the pressure die cast magnesium alloy AZ91D after long-term thermal exposure

The thermal resistance of the pressure die cast magnesium alloy AZ91D is yet not investigated sufficiently. Inorder to assess the effect of a thermal exposure on the microstructural stability and the mechanical properties, the alloyAZ91D is subjected to a long-term annealing for 1 000 h at 80 °C, 100 °C, 120 °C, 150 °C, 180 °C and 200 °C. After theannealing, the microstructural appearance of the material is investigated by light and scanning electron microscopy andcompared with the as-cast condition. Furthermore, tensile tests, hardness measurements and fracture toughness tests arecarried out and the measured values are discussed on the basis of the microstructural changes. The results reveal thedistinct correlation between the microstructural changes, especially the precipitation of discontinuous and continuousβ-particles (Mg17 Al12), and the mechanical properties.

Harbin to Complete Construction of the Aluminium-Magnesium Alloy Base in 2011

Harbin City is to start the construction of the aluminium-magnesium alloy base in Pingfang District this year. The project is expected to

Effect of joining temperature on microstructure and properties of Mg/Al diffusion bonded joints

Basing on vacuum diffusion bonding technique,Mg1 and Al1060 were welded under different welding temperatures.Inspection equipment such as scanning electron microscopy,energy dispersive spectroscopy,X-ray diffractometer,and tensile machine were applied to observe and investigate the microstructure,phase composition and mechanical property of Mg/Al diffusion welding joints.The results indic-ate that Mg1/Al1060 diffusion layers generate in the joints,and the thickness progressively increases with ascending welding temperature.From Al to Mg side,diffusion layers are comprised of Mg2Al3,Mg17Al12,and Mg17Al12+Mg based solid solutions sequentially.The shear resistance of the joints increases and then decreases with the increasing welding temperature.At 440℃,the maximal shear strength of 13 MPa can be obtained,and fracture results from Mg2Al3 phase near Al side.

Thermodynamics of clayedrug complex dispersions: Isothermal titration calorimetry and high-performance liquid chromatography

An understanding of the thermodynamics of the complexation process utilized in sustaining drug release in clay matrices is of great importance.Several characterisation techniques as well as isothermal calorimetry were utilized in investigating the adsorption process of a model cationic drug(diltiazem hydrochloride,DIL)onto a pharmaceutical clay system(magnesium aluminium silicate,MAS).X-ray powder diffraction(XRPD),attenuated total reflectance Fourier transform infrared spectroscopy(ATRFTIR)and optical microscopy confirmed the successful formation of the DIL-MAS complexes.Drug quantification from the complexes demonstrated variable behaviour in the differing media used with DIL degrading to desacetyl diltiazem hydrochloride(DC-DIL)in the 2 M HCl media.Here also,the authors report for the first time two binding processes that occurred for DIL and MAS.A competitor binding model was thus proposed and the thermodynamics obtained suggested their binding processes to be enthalpy driven and entropically unfavourable.This information is of great importance for a formulator as care and consideration should be given with appropriate media selection as well as the nature of binding in complexes.

新型泛碱抑制剂的制备及应用

为研究可溶性金属盐对水泥的泛碱抑制效果,配制了氯化镁的水溶液和乙醇溶液、氯化铝的水溶液和乙醇溶液,并分别涂刷在水泥试块表面进行试验,利用Image-pro plus软件进行了水泥试块泛碱程度的定量分析。结果表明:氯化镁溶液和氯化铝溶液均对水泥泛碱有较好的抑制作用,泛碱抑制效果顺序为:50%氯化铝水溶液>45%氯化铝乙醇溶液>30%氯化镁乙醇溶液>30%氯化镁水溶液。XRD表明:可溶性金属盐能和水泥水化产物氢氧化钙发生化学反应,生成难溶性沉淀,吸附在水泥颗粒表面形成保护层,阻止水泥水化的钙离子从内部迁移析出,从而抑制泛碱现象。

AstraZeneca公司向FDA提出aspirin／esomeprazole的NDA

英瑞制药商AstraZeneca公司向美国FDA提出新药上市申请（NDA），寻求批准它的小剂量阿司匹林与esomeprazole magnesium复方产品，用于降低存在胃和／或十二指肠溃疡危险的病人出现与小剂量阿司匹林有关的这种危险。同时，该公司也为Nexium（esomeprazole Mg）用于降低小剂量阿司匹林相关性胃和／或十二指肠溃疡危险提出一项补充NDA申请（sNDA）。Nexium已获准用于存在发展胃溃疡危险的病人连续用非甾体抗炎药（NsAID）治疗时出现与此有关的胃溃疡危险。

乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病的效果及对微环境炎症的影响

目的分析乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病的效果及对微环境炎症的影响。方法选择2021年1月至2022年3月我院收治的80例妊娠期高血压疾病患者作为研究对象,以随机数字表法将其分为对照组和观察组,每组40例。对照组给予硫酸镁、阿司匹林治疗,观察组在对照组治疗基础上加施乌拉地尔治疗。比较两组的治疗效果。结果治疗后,观察组的收缩压、舒张压、尿蛋白含量低于对照组(P<0.05)。治疗后,观察组的可溶性白细胞介素-2受体(sIL-2R)、核因子-κB(NF-κB)、高迁移率族蛋白B1(HMGB1)水平低于对照组(P<0.05)。治疗后,观察组的内皮素-1(ET-1)水平低于对照组,血管内皮生长因子(VEGF)、血小板内皮细胞黏附分子-1(PECAM-1)水平高于对照组(P<0.05)。观察组的不良妊娠总发生率显著低于对照组(P<0.05)。结论乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病不仅能改善微环境炎症及血管内皮功能,提高血压控制效果,还能减少不良妊娠结局发生,值得临床进一步推广及应用。

药用辅料硅酸镁铝(IB型)黏度测定方法探讨

目的:确定硅酸镁铝(IB型)登记备案标准中黏度测定方法是否可行。方法:采用棒状高速搅拌器及旋转黏度计考察硅酸镁铝(IB型)黏度,采用破壁机及旋转黏度计考察硅酸镁铝(IB型)黏度。结果:采用棒状高速搅拌器及旋转黏度计考察硅酸镁铝(IB型)黏度时,样品均不符合规定,采用破壁机及旋转黏度计考察硅酸镁铝(IB型)黏度时,样品均符合规定。结论:硅酸镁铝(IB型)为触变性非牛顿流体,其黏度测定结果受高速搅拌器类型影响较大,建议药用辅料登记备案标准中明确使用的高速搅拌器类型,细化前处理方法。