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Fe含量对金属型铸造Al-Fe合金组织形态的影响 总被引:1,自引:0,他引:1
研究了不同Fe含量的Al-Fe合金在金属型铸造条件下的组织形态.在金属型铸造条件下,亚共晶Al-Fe组织由发达α-Al枝晶与枝晶间隙链接呈网状的细小共晶Al3Fe相所组成;共晶Al-Fe合金组织为弯曲针棒状共晶Al3Fe相和共晶α-Al相共生生长组织;过共晶Al-Fe合金随着Fe含量增加初生Al3Fe相的形态由针棒状向针片状再向长针状转变,初生相周围共晶Al3Fe相依附在初生相表面生长而形成离异共晶组织.并对不同含Fe量时合金的凝固过程进行了分析探讨. 相似文献
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《金属热处理》2019,(11)
采用热分析方法研究了稀土Er对共晶铝铁合金的变质作用。通过OM、XRD、SEM、EDS以及合金在凝固过程中的特征参数综合分析了稀土Er对共晶铝铁合金的作用机理。结果表明:冷却速率为33℃/s时,共晶铝铁合金的凝固过程为:先发生L→α-Al初转变,然后发生L→Al+Al3Fe和L→Al+Al6Fe共晶转变,添加了稀土Er后,在凝固末期发生L→Al+Al3Er转变而生成铝稀土共晶相。初生的Al3Er可以作为初晶α-Al的非均质形核质点,增加了初晶α-Al的形核率,提高了铝铁合金中初晶α-Al开始形核温度,缩短了共晶转变时间。当Er添加量为0.3wt%时,初晶α-Al平均晶粒尺寸达到了最小值21.7μm。当Er添加量为0.5wt%时,初晶α-Al晶粒尺寸增大,且出现了离异共晶组织。 相似文献
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在Al-Fe合金的凝固过程中引入不同功率的超声振动,利用受控凝固和受控振动相结合的实验装置和方法,研究了超声参振对Al-Fe合金熔体温度场以及组织形态和抗拉强度的影响.实验表明:熔体的温度场随振动功率的增加和振动时间的延长而升高,并趋于一个平衡的温度场;超声参振可以显著细化先共晶FeAl3相,Al-Fe合金生长的组织形态的差异主要取决于凝固速度;超声参振凝固的Al-Fe合金的热稳定性好,有良好的应用前景. 相似文献
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二元铝铁合金凝固过程的差热分析研究 总被引:10,自引:3,他引:7
采用差热分析技术研究了二元铝铁合金的凝固过程;考察了冷却速度及合金成分对凝固过程及显微组织的影响,并测定了不同成分铝铁合金的凝固潜热。 相似文献
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电脉冲对Al-12.5%Si合金的孕育变质效应 总被引:1,自引:2,他引:1
研究了Al-12.5%Si合金液存在较大过热度的情况下,电脉冲处理对其凝固组织中初晶相和共晶相的影响。研究发现,经电脉冲处理后的共晶Al-Si合金凝固组织中出现了过共晶组织中才应出现的初晶硅,α-Al枝晶长度变短;差示扫描量热法(DSC)曲线发生变化,电脉冲处理后有明显的初晶硅析出拐点,并且过冷度减小。理论分析表明,电脉冲处理促进了铝硅合金液中Si相的形核与长大,对Al-Si熔体的液态结构产生了影响,从而使其凝固过程和凝固组织发生变化。 相似文献
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Al-Si合金凝固组织中的晕圈现象 总被引:3,自引:0,他引:3
对亚共晶、共晶及过共晶Al-Si合金经熔体温度处理后的凝固组织进行了研究.研究表明,在共晶Al-12wt%Si及过共晶Al-20wt%Si合金的过热处理凝固组织中出现了晕圈,而在亚共晶Al-7wt%Si合金的凝固组织中却没有出现晕圈组织,表明晕圈的形成与合金成分有关.高于一定温度进行熔体温度处理时,共晶(Al-12wt%si)合金的晕圈现象将消失.晕圈现象消失的原因是过热温度改变Al-Si合金的共晶共生区的结果.熔体的过热状态是晕圈组织形成的重要条件. 相似文献
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在本研究中使用Zn-xAl合金液对铝合金表面进行热浸镀,重点研究不同Al含量的Zn-xAl合金液在坩埚中凝固的铸锭组织及在铝基体表面凝固的镀层组织中共晶形貌,分析了不同冷却条件下共晶组织的形成机理及影响因素。结果表明,Zn-xAl合金液铸锭由于冷速较低,属近平衡凝固,共晶组织为典型的片层结构;Zn-xAl合金液镀层的凝固由于冷速过快,冷却速度成为共晶结构的决定因素,共晶组织为非规则共晶形貌,α富Al相呈球形、椭球形或短棒状组织。试验中不同冷却条件下,Zn-xAl合金共晶析出时其领先相均为β富Zn相。 相似文献
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The effect of alloy composition and microstructure on filiform corrosion (FFC) susceptibility was investigated for super-purity based binary model alloys of the systems Al-Mg, Al-Mn, Al-Fe and Al-Cu. Corrosion testing indicated that the presence of electrochemically noble second phase particles is a necessity for FFC to occur. Single phase, solid solution alloys of the Al-Mg, Al-Mn or Al-Fe systems did not support FFC. Heat treatment caused precipitation of the electrochemically noble intermetallic phase FeAl3 in the Al-Fe alloy, resulting in extensive FFC. Precipitation of the phase MnAl6, which has electrochemical properties similar to that of the aluminium rich matrix, by heat treatment did not impair the corrosion properties of the Al-Mn alloy. Significant surface oxidation and magnesium enrichment of the surface oxides by heat treatment did not affect the FFC properties of Al-Mg alloys. However, the solid solution binary Al-Cu alloys exhibited severe FFC. The detrimental effect of copper in solid solution is attributable to selective dissolution phenomena during the corrosion process, whereby copper was locally enriched on the surface as copper-rich particles providing efficient cathodic sites. 相似文献
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The effects of alloying elements, electromagnetic stirring, reheating and semi-solid formation on the microstructure and mechanical properties of Al-Fe alloys prepared by semi-solid formation were studied. It was found that alloying elements and electromagnetic stirring can alter the morphology and growth mode of the iron-rich phase in Al-Fe alloys; and effectively refine the primary Al3Fe phase. In contrast to the microstructure obtained in conventional casting, the Al3Fe phase becomes thin short rod-like instead of thick needle-like; and the dendritic grain structure almost disappears in the semi-solid formation. The Al3Fe phase can be further refined through being dissolved or fused during subsequent reheating. It was also found that the larger extrusion ratio of semi-solid formation causes a greater crushing effect and therefore the Al3Fe phase is more refined and has more uniform distribution. Moreover, Al-Fe alloys prepared by semi-solid formation exhibit excellent mechanical properties at both room and high temperatures. 相似文献
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K. Sampath Ph.D. W. A. Baeslack III Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1994,46(7):41-47
The weldability of dispersion-strengthened, rapidly solidified Al-Fe alloys is limited by the residual hydrogen content, solidification behavior, and the high-temperature deformation behavior of these alloys. Consequently, the selection and application of welding processes and conditions to join these aluminum alloys—either to themselves or with other engineering alloys—must be based on the ability of the welding process conditions to eliminate or minimize the occurrence of fusion zone porosity; “recreate” a microstructure similar to the rapidly solidified, powder metallurgy base alloy; and/or “retain” the superior base alloy microstructure in the weld zone. Toward this end, an understanding of the physical metallurgy and high-temperature deformation characteristics of the dispersion-strengthened, rapidly solidified, powder metallurgy Al-Fe alloys and the effects of welding process conditions and parameters on weld solidification behavior and microstructural development in the weld zone will enable one to optimize welding conditions to obtain desirable combinations of weld microstructure and mechanical properties. 相似文献
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利用Cu元素的含量变化研究了Al8Cu4Er相的形成与演变规律及其对Al-Zn-Mg-Er-Sc-Zr合金腐蚀性能的影响。结果表明:随着Cu含量的增加,合金晶粒得到显著细化,但同时固溶态合金不同类型的残余相增多;Al8Cu4Er相与Al-Fe相存在伴生关系,二者通过Cu与Fe交互作用实现相的转化,且可表述为如下关系式: ;不同成分合金的晶间腐蚀均表现出与残余相密切相关的点蚀特征,含Cu、Er的Al-Fe相虽然具有更小的腐蚀坑尺寸,但网状分布特征使腐蚀深度有所增加;而具有更好耐蚀性能的Al8Cu4Er则因相的粗化和它与Al-Fe相的伴生关系导致合金耐蚀性能严重下降。 相似文献
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