Failure resistance of structural cast aluminum alloys

Scientific Production Association, Institute of Aviation Materials. Scientific Production Association, Institute of Light Alloys. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 36–38, May, 1991.     

ZL系列铸铝合金的微弧氧化

对含硅量为 8 %～ 12 %的ZL系列铸铝合金的微弧氧化工艺条件、膜层结构以及成膜过程进行了研究。结果表明 :采用不对称交变电压和在以硅酸钠为主要成分的复合电解液体系中 ,铸铝合金表面可获得一层性能优异的微弧氧化膜层。电子能谱 (EDS)和X射线衍射 (XRD)分析结果表明微弧氧化膜主要由Al,Si和O元素组成 ,膜的相结构主要为 η Al2 O3 ,α Al2 O3 和SiO2 ,并含有γ Al2 O3 和Mg ,W ,Cu等元素的氧化物。扫描电镜 (SEM)分析表明微弧氧化膜由致密层 (内层 )和疏松层 (外层 )构成 ,疏松层表面存在许多气孔 ,而致密层完整光滑 ,具有较高的显微硬度和优异的耐磨耐蚀性能     

Heat treatment of aluminum alloys AL9 and AL34

Conclusions Stepped heating for solutioning and aging improves the mechanical properties of alloys AL9 and AL34 and shortens the heat treatment time.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 58–59, October, 1979.     

Diagnosis of oxide films in cast aluminum alloys

Aluminum (Al) alloy castings often contain many defects, such as micro-shrinkage, gas pores, shrinkage pores, hot tearing, and oxide film entrapment. When oxide films are entrapped in Al alloy castings, they are very difficult to identify simply by optical observation. In this study we used an auto-scanning eddy current testing method to detect oxide films entrapped in Al alloy castings. The detection signal and the measurement data were confirmed by scanning electron microscope (SEM) observation and partly backed-up by the ultrasonic-vibration method.     

Molten metal processing of advanced cast aluminum alloys

Premium quality aluminum alloy castings are used extensively in various applications requiring a high strength-to-weight ratio, such as aerospace, automotive and other structural components. The mechanical properties in these structure-sensitive alloys are determined primarily by the secondary dendrite arm spacing and the morphology of interdendritic phases. In addition, the amount of porosity in the casting and the inclusion concentration have a strong influence on fracture, fatigue and impact properties. During the production of the casting, various molten metal processing techniques can be implemented to control these microstructural parameters. These melt treatments include grain refinement with Ti-B, eutectic modification with strontium or sodium, degassing with purge gases and filtration of inclusions. The efficiency of these treatments determines the quality of the cast component.     

铸造A356铝合金的低周疲劳行为

研究不同加钛方式和钛含量对铸造A356铝合金常温低周疲劳行为的影响,分析合金疲劳断口的形貌特征.结果表明:4种A356合金均表现出明显的循环硬化行为,但Ti含量(质量分数)为0.14%的合金比Ti含量为0.10%的合金具有更高的循环硬化率.在低应变时,加钛方式对合金的循环硬化影响相近;而在高应变时,电解加钛A356合金...     

Comparison of earing behavior between continuous cast and direct chill cast AA 5182 aluminum alloys during cold rolling and annealing

The evolution of texture and earing during rolling of continuous cast (CC) and direct chill (DC) cast AA 5182 aluminum alloys was investigated. The results showed that the CC alloy possessed a significantly weaker cube texture than the DC alloy after annealing at 454 °C for 3 h. The evolution of texture and earing during rolling was strongly affected by the initial texture. The 45° earing value of the CC alloy increased with increasing rolling reduction, while the 0/90° earing value of the DC alloy decreased. After 45% cold rolling reduction, the deep-drawn cup of the DC alloy exhibited eight ears at 0°, 45° and 90° to the rolling direction. The DC sheet with minimum earing was obtained at about 83% rolling reduction. The evolution of texture and earing during annealing of the CC and DC alloys was compared. An empirical relationship between the earing value and texture volume fractions was established. Minimization of earing could be achieved by balancing the cube, r-cube and β fiber components.     

Heat treatment of vacuum high pressure die cast magnesium alloy AZ91

Alloys produced by high pressure die casting (HPDC) are generally considered non-heat treatable because trapped gas pores tend to expand, causing surface blistering and bulk distortion. In this paper, vacuum assisted HPDC of magnesium alloy AZ91 was used, and the properties were assessed. The specimens produced using vacuum die casting contain less porosity. Little improvement in yield strength by applying vacuum is found, although a small increase in elongation is observed. A conventional heat treatment applied to the vacuum die cast AZ91 shows pronounced precipitation hardening during aging, especially after a prior solution treatment. However, an associated improvement in yield strength after aging is not observed, and this is related to the decreased contribution of the ‘skin’ effect as a result of grain growth.