6060铝合金生产工艺研究

设计了6060铝合金车用型材的熔铸、挤压工艺,并通过室温托伸实验分析了影响6060合金力学性能的因素。结果表明：将6060铝合金中强化相元素Si、Mg按中上限控制可保证材料力学性能要求,挤压温度及速度对合金性能影响较小。经过T5热处理的6060合金,其力学性能达到一定指标,且材料尺寸精度和表面平直度较T6状态好。     

The Effect of Iron Content on Microstructure and Mechanical Properties of A356 Cast Alloy

In the present study, microstructure and mechanical properties of A356 alloy including various amounts (0.2 to 1.2 wt pct) of iron were investigated. The alloys were produced by conventional gravity sand casting method. In order to determine the effect of iron addition to A356, optical and scanning electron microscopes (SEM/EDS) were used for microstructural examinations, and X-ray diffraction (XRD) analysis was carried out for phase characterization. Tensile tests were also conducted in order to determine effect of the Fe content on mechanical properties. It was found that as the Fe content of A356 was increased, the secondary dendrite arm spacing (SDAS) was decreased and the morphology of Al-Si eutectic became finer. From XRD examinations, different iron-based intermetallic compounds (β-Al₅FeSi and α-Al₈Fe₂Si) formations were observed. It was also observed that as iron content increased, α-Al₈Fe₂Si intermetallic was transformed into β-Al₅FeSi intermetallic. The tensile test results revealed that tensile strength and elongation values were reduced by increasing Fe content. It was also determined that β-Al₅FeSi intermetallics were more negatively effective on tensile strength than α-Al₈Fe₂Si intermetallics.     

铸造铝合金的杂质控制

从理论上分析了铸造铝合金中主要杂质对铝合金性能的影响, 根据不同用途的铝合金允许杂质含量也不同这一特点提出了杂质控制在铝合金生产上的指导作用, 从而达到资源合理配置, 减少废品, 降低成本的目的。     

铝铁中间合金铁含量的检查

本文根据现有的资料,认真进行了条件试验,制定了重铬酸钾滴定法检查铝铁中间合金中铁量。经反复验证,认为此方法结果准确、分析速度快、操作简便。可以用于生产检查。     

铸铁材质铝锭模生产实践

通过比较灰口铸铁、球墨铸铁、蠕墨铸铁生产的铝锭模成分、金相组织和性能,设计了铝锭模生产所用的蠕墨铸铁成分、组织、工艺参数。采用共晶点附近成分,碳当量(CE)为4.16,蠕化率为50%,基体组织为50%珠光体+铁素体的蠕墨铸铁作为铝锭模的生产材料。生产实践证明:用作铝锭模材料,蠕墨铸铁使用寿命是灰铸铁(HT250)和球墨铸铁的2倍多。     

铝和钛含量对镍基铸造高温合金性能的影响

研究了拉伸和持久强度提高,塑性、冷热疲劳和焊接性能相应降低,尤其是Ti元素的作用尤为明显.还发现合金中的γ'相、MC相和(γ+γ')共晶组织的数量和尺寸是影响合金性能的重要因素.     

铸造温度对铝中含氢量影响规律的研究

通过测试溜槽中不同温度下铝熔体中氢含量,发现铝中氢含量随着铸造温度升高而升高,每升高1℃,铝中氢含量约升高0．013mL／100gAl;铸造开始时铝中氢含量高于铸造过程铝中氢含量。     

The Effect of Melt Conditioning on Segregation of Solute Elements and Nucleation of Aluminum Grains in a Twin Roll Cast Aluminum Alloy

An aluminum alloy was cast by a laboratory scale horizontal twin roll caster with or without melt conditioning by the intensive shearing prior to solidification and then examined by high-resolution electron microscopy. The combined twin roll casting process with solidification formed channels and induced centerline segregation without the conditioning. In comparison, the melt conditioning minimized the severe segregation on the surface as well as at the centerline. Furthermore, large amounts of solute elements were uniformly distributed along grain boundaries or interdendritic regions. Analytical electron microscopy detected a fine oxide particle or a fragmented aluminum particle particularly at the center region of one nucleated aluminum grain. In addition, large oxide particles of about 1 to 5 μm nucleated aluminum grains easily due to low undercooling necessary for the heterogeneous nucleation, whereas small oxides with the size of about 100 to 200 nm requiring large undercooling were pushed along the grain boundaries instead of contributing to the nucleation. The enhanced nucleation of aluminum grains and well-distributed solute atoms in the melt by the melt conditioning resulted in the minimization of macro- and micro-segregations and the formation of a uniform microstructure.     

样模的外观结构对A356.2铸造铝合金中Si偏析的影响

介绍了A356.2铸造铝合金生产过程中,采用不同的样模做化学成分取样分析时,Si的偏析情况。结果显示,采用改进后的样模,液态样的分析数据结果能更准确的代表成品样的分析结果,从而有效控制A356.2铸造铝合金的生产过程。     

工艺参数对连续铸轧铝合金组织的影响

本文研究了铸轧速度、辊缝等铸轧工艺参数对铸轧板显微组织的影响。结果表明,过高的铸轧速度导致板材中心偏析严重,小辊缝有利于控制化合物及晶粒的尺寸。     

Microstructure,Intermetallic Phases,and Fractography of the Cast Al-5.8Zn-2.2Mg-2.5Cu Alloy by Controlled Diffusion Solidification

Metallurgical and Materials Transactions A - The cast specimens for this study were prepared with a final composition of Al-5.8Zn-2.2Mg-2.5Cu alloy by using a relatively new casting process that is...     

稀土对高Ni-Cr铸铁石墨的变质作用

采用金相和电镜等手段对稀土在高Ｎｉ－Ｃｒ铸铁中的行为进行了研究。结果表明：稀土可以改善高Ｎｉ－Ｃｒ铸铁石墨的形态及分布，使之由长条状向短厚状过渡。并且随着稀土加入量增多，石墨数量增加。     

稀土对Fe－C－Al－Si铸铁组织和性能的影响

本文研究了稀土对Ｆｅ－Ｃ－Ａｌ－Ｓｉ铸铁的石墨形态，基体组织，力学性能及激冷倾向的影响。随１~＃稀土量增加，石墨由片状向蠕虫状转变较快，但由蠕虫状向球状转变很慢，故具有较大的蠕化范围。铸铁的强度在０．３～１．２％１~＃稀土范围内随稀土的增加而增加，但在１．２～２．０％范围内稍有下降。稀土具有较强的促进激冷倾向的能力，而铝具有抑制或消除激冷倾向的作用。孕育能显著降低激冷倾向，且其效果比普通铸铁更明显。并对有关机理进行了讨论。     

钇含量对CoNiCrAlY合金微观组织的影响

分别采用真空感应熔炼及真空惰气雾化的方法制备了CoNiCrAlY铸锭及粉末,并对其铸态组织进行了研究。结果表明:随着钇含量的增加,钇偏聚程度也逐渐增大,在铸锭铸态组织中存在明显的枝晶组织,钇含量较低时其形貌呈现细长条状。而当钇含量达到1.40%时,铸锭中枝晶开始呈现鱼骨状。另外,研究表明粉末中的显微组织与铸锭中相似,但当钇含量为0.61%时,钇的偏聚不明显。     

Microstructural Inclusion Influence on Fatigue of a Cast A356 Aluminum Alloy

We examine the dependence of fatigue properties on the different size scale microstructural inclusions of a cast A356 aluminum alloy in order to quantify the structure-property relations. Scanning electron microscopy (SEM) analysis was performed on fatigue specimens that included three different dendrite cell sizes (DCSs). Where past studies have focused upon DCSs or pore size effects on fatigue life, this study includes other metrics such as nearest neighbor distance (NND) of inclusions, inclusion distance to the free surface, and inclusion type (porosity or oxides). The present study is necessary to separate the effects of numerous microstructural inclusions that have a confounding effect on the fatigue life. The results clearly showed that the maximum pore size (MPS), NND of gas pores, and DCS all can influence the fatigue life. These conclusions are presumed to be typical of other cast alloys with similar second-phase constituents and inclusions. As such, the inclusion-property relations of this work were employed in a microstructure-based fatigue model operating on the crack incubation and MSC with good results.     

稀土导电铝合金的铸态组织和相组成

本文利用光学显微镜、扫描电镜、Ｘ射线衍射仪等，研究了Ｌａ、Ｃｅ对工业纯铝铸态组织和相组成的影响。结果表明，Ｌａ、Ｃｅ能细化工业纯铝的铸态组织，并和Ｆｅ、Ｓｉ等元素结合生成了二元或三元稀土化合物相。     

Sr含量对4004铝合金铸锭变质效果的研究

研究了Sr加入量分别为0．01％、0．015％、0．02％,变质保温时间分别为60min、80min、100min,对4004铝合金变质效果的影响。结果表明：Sr加入量低于0．015％、变质保温时间小于80min时,合金组织和力学性能均没有达到完全变质状态;Sr加入量0．015％、变质保温时间80min时,4004铝合金变质效果最好,合金组织中的初晶硅转变为细小的圆状或短棒状,共晶硅也由片状或针状转变为纤维状,合金的抗拉强度和伸长率达到最大值193MPa和4．2％;Sr加入量超过0．015％、变质保温时间超过80min时,随着加入量的增加,合金组织开始变得粗大,抗拉强度随着下降。