Effect of Ti and Zr elements with equal mass ratio on microstructure and corrosion resistance of Zn-11Al-3Mg alloy

In this study, the effect of Ti and Zr elements with equal mass ratio on microstructure and corrosion resistance of Zn-11Al-3Mg alloy was investigated. The microstructure was significantly refined and Al-rich phase transformed from dendrite to petal-like with the addition of Zr and Ti elements, due to the Al₃(Ti_xZr_{1 − x}) phase as the nucleation substrate. The corrosion resistance of Zn-11Al-3Mg-x(Ti,Zr) alloy was effectively improved. Moreover, the corrosion products of Zn-Al-Mg alloy were not changed by the addition of Ti and Zr, which are mainly composed of Zn₅(OH)₈Cl₂·H₂O and Zn₆Al₂(OH)₁₆CO₃·4H₂O.     

微弧氧化Mg-3Al-1Zn镁合金应力腐蚀和腐蚀疲劳行为研究

本文主要对微弧氧化Mg-3Al-1Zn镁合金在空气和3.5 wt.%硫酸钠溶液两种环境下的应力腐蚀和腐蚀疲劳行为进行研究,并讨论其相互关系。微弧氧化处理后,Mg-3Al-1Zn镁合金的耐蚀性能得到明显改善。与Mg-3Al-1Zn镁合金基体相比,在空气中,微弧氧化后合金的应力腐蚀和腐蚀疲劳强度均下降了大约10 MPa。在3.5 wt.%硫酸钠溶液环境中,微弧氧化后合金的腐蚀疲劳性能仍然是恶化的,但是应力腐蚀强度却得到了显著改善,从58.24 MPa提高至202.08 MPa。这表明材料的力学性能（应力腐蚀和腐蚀疲劳）并不是与其腐蚀性能完全保持线性关系的。微弧氧化处理后镁合金在空气中的应力腐蚀断口为韧性断裂,在硫酸钠溶液环境中为解理断裂。而其腐蚀疲劳断口不论是在空气中还是在腐蚀环境中均为解理断裂。这主要是由于腐蚀环境和变换循环载荷的影响,两者共同作用将会加速裂纹扩展。这表明,周围环境和加载类型对材料断裂机理有重要影响。     

Effect of suspended solids on the flow-induced corrosion of a modified Al-2.5Mg alloy in arabian gulf water

Suspended solids increase the rate of corrosion and decrease the resistance of a modified Al-2.5Mg alloy to pitting in Arabian Gulf water. It has been shown by electrochemical studies that the pitting potential of the alloy shifts to more negative values in the presence of suspended solids. The rate of mass transfer and the limiting current is significantly increased by suspended particles.     

Effects of microstructures on corrosion and stress corrosion behaviors of an Al-12.1 at.% Zn alloy

Various heat treatments of an Al-12.1 at.% Zn alloy would bring forth various types of microstructures such as solid solution (SS), continuous precipitation (CP), and discontinuous precipitation (DP), each of which contain respective shares of distribution of the aluminum-rich phases (α ₀, α) and the zinc-rich phase (β), and the corrosion behaviors of the said alloy may be affected as a result. Electrochemical measurements conducted in a 3 wt.% NaCl solution indicate that respective corrosion rates should be evinced in the following order: supersaturated SS<DP<CP. The difference in microstructures can also exert an influence on stress corrosion cracking (SCC) of the said alloy. Stress corrosion cracks propagate predominantly in an intercrystalline mode. However, the severe corrosion of precipitation sites may incur a change in crack propagation under applied stress. In that case, patches of transgranular fractures are found interspersed in the intergranular mode.     

Mg对Al-5％Fe合金组织的影响

研究了Mg对Al-5％Fe合金中Al3Fe相形貌的影响。研究发现，Mg对Al-5％Fe合金中Al3Fe相的形貌产生较大影响。未加入Mg时，初生Al3Fe相大多为针状，少量为花朵状。加入Mg后，组织得到改善：初生针状Al3Fe相变小，有向花朵状转变的趋势，共晶A13Fe相长成针点状；当Mg量超过0．5％后，初生Al3Fe相的分枝加剧。     

Mg对Al-5%Fe合金组织的影响

研究了Mg对Al-5?合金中Al3Fe相形貌的影响.研究发现,Mg对Al-5?合金中Al3Fe相的形貌产生较大影响.未加入Mg时,初生Al3Fe相大多为针状,少量为花朵状.加入Mg后,组织得到改善:初生针状Al3Fe相变小,有向花朵状转变的趋势,共晶Al3Fe相长成针点状;当Mg量超过0.5%后,初生Al3Fe相的分枝加剧.     

Decomposition studies of a liquisol quenched Al-33 at.% Mg alloy

X-ray and electron metallographic studies were undertaken on an aluminum-33 at.% magnesium alloy rapidly quenched from the melt by the “gun” technique. A small supersaturation of Mg in Al and two metastable intermediate phases were detected. These phases were found to display complex decomposition behavior on annealing at temperatures up to 300°C.     

Al-4.6Zn-2.58Mg合金热变形工艺研究

在工业化生产条件下,采用半连续铸造、自由锻造、固溶和时效处理技术制备A l-4.6Zn-2.58Mg合金锻件。采用热加工模拟方法优化该合金的热加工工艺。试验结果表明:该合金高温压缩变形时的流变应力随变形温度的升高而减小,随变形速率的提高而增大。合金在420℃以下热变形,热变形组织主要为动态回复组织;在420℃以上热变形,热变形组织有动态再结晶发生。在400℃~420℃之间热压缩变形,变形抗力比较小;380℃~420℃时铸态塑性最好。该合金较适宜的热加工温度范围为400℃~420℃。     

Dynamic recrystallization during hot torsion of Al-9Mg alloy

1INTR0DUCTIONTheoccurrenceofdynamicrecrystallizationduringthehotdeformationofthosemetalsthatrecoveronlyrelativelyslowlyhasbeenwelles-tablished.Thesemetals,suchaslead,gold,sil-ver,nickel,copper,y-ironandall0ysbasedonthem,havel0wstackingfaultenergies.Inre-centyearslithasbeenfoundthatthedynamicrecrystallizationcanoccurinaluminiumalloyswithrelativelyhigherstackingfaultenergy(SFE)[l~lo].TruszkowskietalLll]havesug-gestedthattheadditionofl%MgtoAlreducetheSFEfrom200J/m2toabout5OJ/m',there-for…     

Al-4.3Zn-1.4Mg合金均匀化处理工艺研究

采用光学显微镜、差热分析、扫描电镜、能谱分析,研究了Al-4.3Zn-1.4Mg合金的铸态组织以及铸锭经不同均匀化制度处理后的微观组织。结果表明,Al-4.3Zn-1.4Mg合金的铸态组织中主要存在T相、Mg2Si相和AlFeMn相三种结晶相;铸锭过烧温度为479℃;铸锭经均匀化处理后,T相及Mg2Si相均回溶入基体,而主要含AlFeMn的过剩结晶相仅发生部分溶解。     

Al-5.0Cu合金腐蚀性能的试验研究

为调查变形铝合金Al-5.0Cu的腐蚀性能,用ASTM标准试验方法研究了该合金的剥落腐蚀性能。试验结果表明,合金经历的热加工温度影响其最终微观结构,试验的所有合金试样呈现不同程度的再结晶组织,且晶粒随温度升高而逐渐变大。较高加工温度下,形成的粗大晶粒结构有利于提高其腐蚀抵抗力。     

The influence of volume fraction of amorphous phase on corrosion resistance of Mg67Zn 29Ca 4 alloy

The aim of this study was to investigate the structure and corrosion resistance of amorphous, amorphous‐crystalline, and crystalline Mg₆₇Zn₂₉Ca₄ alloy for biodegradable applications. This paper presents a preparation method and results of the structural characterization and corrosion resistance analysis of the material. Samples were prepared in the form of 3 mm diameter rods. The structure of the alloy was examined with the use of X‐ray diffractometry and scanning electron microscopy. The thermal properties of the samples were examined with differential scanning calorimetry (DSC). Results of DSC analysis were used to determine heat treatment temperatures, allowing to obtain different fractures of crystalline phase in the material. Corrosion resistance of heat‐treated samples was investigated by immersion tests and electrochemical measurements performed in the simulated body fluid. The X‐ray diffraction results confirmed that the prepared Mg₆₇Zn₂₉Ca₄ alloy's structure is fully amorphous. After heat treatment, samples with different fractions of amorphous phase in the structure were obtained. Immersion tests of the samples showed that the structure significantly influenced corrosion resistance in examined materials. It should be pointed out, that certain amounts of crystalline phase in amorphous matrix can greatly improve the corrosion resistance of Mg₆₇Zn₂₉Ca₄ alloy.     

Effect of vacuum heating on the corrosion resistance of Al-4.5Zn-2Mg

Conclusion Preliminary heat treatment in vacuum of Al-Zn-Mg alloys improves the stress corrosion resistance. One of the probable reasons for this effect is the impoverishment of the surface layer in magnesium and zinc.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 10–13, July, 1978.     

Investigation of the influence of iron-containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4

The corrosion resistance of aluminium surfaces is closely linked to the surface state after a grinding process. For years, iron-containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary. For the current investigation, specimens of a technical Al-Si alloy from the same batch were used. The test specimens were mechanically ground with various resin-bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron-containing abrasives on the corrosion behaviour of the Al–Si alloy. However, the most sensitive measuring method (electrochemical noise) showed differences in the surface activity depending on the type of abrasive.     

喷射成形Al-22Si-5Fe-3Cu-1Mg合金的热变形行为(英文)

通过等温压缩试验,对喷射成形Al-22Si-5Fe-3Cu-1Mg合金在试验温度为350～500℃和应变速率为0.001～0.1s1条件下的热变形行为进行研究。在开始变形阶段,加工硬化是主要的影响因素,流变应力迅速达到最大值,随后持续降低,这时加工硬化的趋势和流变软化的趋势相平衡,应力曲线几乎趋于稳定。采用双曲正弦函数建立的本构方程来描述合金的变形行为,热变形激活能为312.65kJ/mol。为了防止初晶硅相的长大,热挤压的温度不超过500℃。     

High-temperature corrosion of Ti and Ti-6Al-4V alloy

Pure titanium and Ti-6Al-4V were exposed at 750°C in an H₂/H₂O/H₂S P_{O 2}10^–18 Pa and P_{S 2}10^–1 Pa), H₂/H₂O (P_{O 2}10^–18 Pa) and air environments for up to 240 hr. The corrosion kinetics, obtained by the discontinuous gravimetric method, showed that the sulfidation/oxidation kinetics were linear for Ti and linear-parabolic for Ti-6Al-4V in the H₂/H₂O/H₂S environment. Both materials obeyed parabolic rate laws in the H₂/H₂O atmosphere after a transient period, and linear-parabolic rate laws in air. After exposure to the H₂/H₂O/H₂S atmosphere, the titanium specimen displayed a double scale of TiO₂ with an intervening TiS₂ film between the double-layered scale of TiO₂ and the substrate. Ti-6Al-4V also contained a double layer of TiO₂ together with a stratum consisting of Al₂S₃, TiS₂ and vanadium sulfide at the junction of the inner TiO₂ layer and substrate. Some Al₂O₃ precipitated in the external portion of the outer TiO₂ layer. Following oxidation in the low-P_{O 2} atmosphere a double-layered oxide of TiO₂ scale formed on both Ti and Ti-6Al-4V. The scale on Ti-6Al-4V also contained an -Al₂O₃ film situated between the outer and inner (TiO₂) layers. For both materials, multilayered-scale formation characterized air oxidation. In detail a multilayered oxide scale of TiO₂ formed on the air-oxidized Ti, while a multilayered oxide scale with alternating layers of Al₂O₃/TiO₂ developed on Ti-6Al-4V oxidized in air.     

应变条件对Al-6Mg合金拉伸行为的影响

研究了Al-6Mg合金的拉伸行为.结果表明,合金在高温和高应变速率下发生脆性断裂,端口呈沿晶和解理混合状.微量元素促进脆化的发生.     

Al-4.3Zn-1.4Mg合金板材的时效工艺研究

通过拉伸性能测定、电导率测定、显微组织结构分析等方法,研究了不同单级时效处理条件下Al-4.3Zn-1.4Mg铝合金的力学性能、电导率和显微组织结构。结果表明,试验铝合金的峰时效(T6)制度为120℃24 h,该铝合金的抗拉强度达到438 N/mm2,基体内有大量细小的沉淀相析出,晶界析出相呈连续分布。120℃过时效处理后,晶界析出相呈断续分布,有明显的晶界无析出带。