V对Fe3Al基有序合金力学性能的影响

研究了微量Ｖ对ＤＯ３型Ｆｅ３Ａｌ基合金伸性能和组织结构的影响。结果表明，Ｖ可细化晶粒，改善Ｆｅ３Ａｌ合金室温强度和塑性，室温伸断口也由穿晶解理型转变为加沿晶混合型，Ｖ还使Ｆｅ３Ａｌ合金高温强度峰值对应的温度提高约２００℃，从而提高Ｆｅ３Ａｌ合金高温强度峰值对应用温度提高约２００℃，从而提高Ｆｅ３Ａｌ合金使用温度。     

金属间化合物／Al2O3陶瓷复合材料研究新进展

本文主要介绍了Ｎｉ－Ａｌ／Ａｌ２Ｏ３、Ｔｉ－Ａｌ／Ａｌ２Ｏ３和Ｆｅ－Ａｌ／Ａｌ２Ｏ３三种复合材料的最新研究进展情况,对它们的最新研究动态进行了综述。着重介绍了Ｆｅ－Ａｌ／Ａｌ２Ｏ３的研究进展,并认为Ｆｅ－Ａｌ／Ａｌ２Ｏ３是一种应用前景非常广阔的新型材料,添加合金元素是进一步提高其性能的重要途径。     

自蔓延高温合成TiC—Al2O3—Fe系金属陶瓷的致密化研究

采用ＳＨＳ／ＰＨＩＰ工艺制备了致密的ＴｉＣ－Ａｌ２Ｏ３－Ｆｅ系金属陶瓷，研究了延迟时间，高压特续时间，压力及Ｆｅ含量对合成ＴｉＣ－Ａｌ２Ｏ３－Ｆｅ金属陶瓷实度的影响，结果表明，采用ＳＨＳ／ＰＨＩＰ技术制备了ＴｉＣ－Ａｌ２Ｏ３－Ｆｅ系金属陶瓷时，合成产物中气体的排放，液相的存在及组成相之间的润湿性是制备密实材料的关键。     

掺杂聚苯胺磁化率的研究

分别研究了浓Ｈ２ＳＯ４掺杂本征态聚苯胺（ＰＡｎ）、ＨＣｌ掺杂ＰＡｎ以及ＦｅＣｌ３掺杂这两种聚安在地的磁化率。通过研究磁化率的变化曲线,我们得到了一些有意义的结果：浓Ｈ２ＳＯ４掺杂ＰＡａ和ＨＣｌ掺杂ＰＡｎ的磁化率变化规律不同;ＦｅＣｌ３掺杂浓Ｈ２ＳＯ４－ＰＡｎ材料可以获得比ＦｅＣｌ３掺杂ＨＣｌ－ＰＡｎ材料更高的磁化率;ＦｅＣｌ３在掺杂ＨＣｌ－ＰＡｎ材料和浓Ｈ２ＳＯ４－ＰＡｎ材料时,ＦｅＣｌ３在这两种     

STUDY FOR MECHANICAL ALLOYING OF Fe─M BY MOSSBAUER SPECTROSCOPY

将Ｆｅ－Ｍ（Ｍ＝Ｃ５ＳｉＯ２Ａｌ２Ｏ３）混合物在Ａｒ中高能球磨５６ｇ后测量Ｍｏｓｂａｕｅｒ谱，结果表明，（Ｆｅ）２－（ＳｉＯ２）１仍为Ｆｅ和ＳｉＯ２的机械混合物：（Ｆｅ）６－（Ｃ）３已完全合金化，生成两种Ｆｅ３Ｃ；（Ｆｅ）２－（Ａｌ２Ｏ３）１则成为Ｆｅ（７３％），尖晶石型的ＦｅＡｌ２Ｏ４）２２％），ｑｑｎｔＦｅ的团聚族（５％）和Ａｌ２Ｏ３的混合物。     

Fe_3Al金属间化合物强韧化研究进展

Ｆｅ３Ａｌ基合金作为一种金属间化合物新型结构材料越来越引起人们的重视，极有可能在许多场合得到应用。但是Ｆｅ３Ａｌ合金室温时的低塑性和低的断裂抗力以及高于６００℃时强度的急剧下降妨碍了它的工程应用，本文主要综述近几年来Ｆｅ３Ａｌ金属间化合物机械性能方面的研究情况。     

Fe—Al系金属间化合物本征脆性的电子理论

利用电子理论计算了Ｆｅ３Ａｌ和ＦｅＡｌ金属间化合物的价电子结构和键能。分析了电子分布和晶体键络特性与其室温脆性之间的关系，提出了韧化Ｆｅ－Ａｌ系金属间化合物的可能途径。     

Fe－Al系金属间化合物本征脆性的电子理论

利用电子理论计算了Ｆｅ＿３Ａｌ和ＦｅＡｌ金属间化合物的价电子结构和键能，分析了电子分布和晶体键络特性与其室温脆性之间的关系．提出了韧化Ｆｅ—Ａｌ系金属间化合物的可能途径．     

Fe3Al基合金耐腐蚀性能研究进展

Ｆｅ－Ａｌ基合金是当前金属间化合物研究的热点，本文结合自己的工作总结了国内外Ｆｅ３Ａｌ金属间化合物耐腐蚀性能研究的大量文献，简要地综述了Ｆｅ３Ａｌ基合金高温腐蚀，热腐蚀及水溶液腐蚀性能的发展，并对当前研究中的问题及今后的发展趋势作了论述。     

Fe3Al基合金室温拉伸性能的研究

用扫描电镜、俄歇能谱等对Ｆｅ３Ａｌ基合金的室温拉伸性能进行了研究。结果表明，热处理对性能的影响显著；Ｆｅ３Ａｌ的晶界不存在成分偏析。     

High‐Strength Nanotwinned Al Alloys with 9R Phase

Light‐weight aluminum (Al) alloys have widespread applications. However, most Al alloys have inherently low mechanical strength. Nanotwins can induce high strength and ductility in metallic materials. Yet, introducing high‐density growth twins into Al remains difficult due to its ultrahigh stacking‐fault energy. In this study, it is shown that incorporating merely several atomic percent of Fe solutes into Al enables the formation of nanotwinned (nt) columnar grains with high‐density 9R phase in Al(Fe) solid solutions. The nt Al–Fe alloy coatings reach a maximum hardness of ≈5.5 GPa, one of the strongest binary Al alloys ever created. In situ uniaxial compressions show that the nt Al–Fe alloys populated with 9R phase have flow stress exceeding 1.5 GPa, comparable to high‐strength steels. Molecular dynamics simulations reveal that high strength and hardening ability of Al–Fe alloys arise mainly from the high‐density 9R phase and nanoscale grain sizes.     

Environmental Embrittlement in A_3B-type Intermetallic Alloys

Environmental embrittlement in A3B-type intermetallics based on Ni3Al and Fe3Al has been studied in this paper. For the Ni3Al doped with 120 wt ppm B and Ni,(Al,Cr.Zr) doped with 80 wt ppm B,their elongation and ultimate tensile strength decreased in the sequence:of vacuum > air >hydrogen. while for Ni,(Al,Mn) doped with 400 wt ppm B no envifonmental degradation was ob served, although a -Ni3(Al,Mn) alloy without B showed a decrease in ductility when tested in air in stead of oxygen. It is supposed that boron and hydrogen compete for the occupation of interstitial sites near grain boundaries. If boron content is sufficiently low, hydrogen embrittlement occurs ;however, if its content is sufficiently high. boron addition is capable of eliminating envjronmental ef fect in Ni3Al-based alloysi As to the micromechanism of hydrogen embrittlement in Ni3Al+B. S EM in situ observations showed that both grain boundary decohesion and a high stress concentration con tributed to hydrogen-assisted jntergranu lar cracking in this alloy. For the Fe3Al and Fe3 (Al.Cr) alloys.their mechanical properties depended strongly on grain size / grain shape and testing environment. A strain rate effect on ductiIity and fracture strength was also observed in the Fe3Al and Fe,(Al,Cr)+B aIloys. Preoxidation increased the ductility of the Fe,(Al,Cr)+B alloy. All these results can be rationalized from a hypothesis that surface reaction is the controlling process in embrittling Fe3Al-based alloys.     

Impurity effects on the nucleation and growth of primary Al3(Sc,Zr) phase in Al alloys

Impurity effects on the nucleation and growth of primary Al₃(Sc,Zr) phase have been investigated in high purity Al alloys and commercial purity Al alloys, respectively. In the case of high purity Al alloys, primary Al₃(Sc,Zr) phases were found to be pushed to grain boundaries ahead of the solidification front. Such type of primary Al₃(Sc,Zr) phase did not contribute to the heterogeneous nucleation, and thereby the grain refinement of Al alloys. In the case of commercial purity Al alloys, the presence of Fe, Si, Cu, Mg, Ti, and other impurities significantly enhanced the heterogeneous nucleation of primary Al₃(Sc,Zr) phase. Most primary Al₃(Sc,Zr) phases were found to be located within the α-Al matrix, and kept an identical orientation relationship with the α-Al matrix. Furthermore, the presence of the impurities also changed the growth mode on the primary Al₃(Sc,Zr) phase. In the case of commercial purity Al alloys, a peritectic to eutectic reaction was induced due to the presence of the impurities. A layered growth was observed leading to a narrow particle size distribution. In contrast, in the case of high purity Al alloys, a featureless structure was observed. This investigation demonstrates that impurities and their concentrations are important factors affecting the nucleation and growth of primary Al₃(Sc,Zr) phases, and thereby for the successful grain refinement in Al-based alloys.     

Al-Ni-Fe系铸态合金中的准晶相

系统研究了Al72.5Fe14.5Ni13和Al71Fe5Ni24铸态合金的相组成，发现其中分别存在D—Al72．6Fel4．6Nil2．8和D'—Al70．5Fe10Nil9．5两种十次准晶，它们各自与AlFe和AlNi二元十次准晶相关．实验结果与三元准晶相图的电子浓度特征吻合，说明三元准晶相图的电子浓度特征对确定三元准晶的理想成分和探索准晶新成分有一定的指导作用．     

球磨合成Fe3Al金属间化合物及其固相反应机理

Fe3Al金属间化合物是一种新型耐高温材料,并因其电热和磁性能受到重视。本文研究由铁、铝元素混合粉末利用高能球磨工艺合成Fe3Al。通过对冷焊现象的分析,用适量的有机物有效地控制了机械合金化过程。利用X射线衍射研究了反应物在球磨过程中的结构演变。通过对Fe／Al固相反应热力学的分析,认为Fe／Al原子比相等成分附近,固相反应最容易进行。     

Fe3Si基合金的制备及应用研究进展

Ｆｅ３Ｓｉ基合金具有优异的软磁性能,不仅有希望硅钢片（在高频信息领域）,而且还广泛用作音几视频磁头材料和卡片阅读器用磁头材料。本文综述了Ｆｅ３Ｓｉ基合金的制备工艺及应用,并结合我们的研究工作,分析了其研究现状,简要论述了其发展前景。     

Precipitation of iron-rich intermetallics and mechanical properties of Al–Si–Mg–Fe alloys with Al–5Ti–B

Effects of added Al–5Ti–B master alloys on precipitation of iron-rich intermetallics and mechanical properties of A356 cast alloys with high Fe content (1.5?wt-%) were investigated using image analysis, scanning electron microscopy, and tensile testing. Results show that added Al–5Ti–B has apparent refinement on α (Al) grain size of A356 alloys that have high Fe content. 12?wt-% Al–5Ti–B is beneficial for improving mechanical properties of A356 cast alloys with high Fe content. Improved mechanical properties can be attributed to refined microstructure, the proper amounts of TiB₂ and Ti(AlSi)₃, and decreased porosity. An excessive amount of Al–5Ti–B deteriorates mechanical properties of alloys because it leads to the formation of large secondary intermetallics and increased porosity.     

The effects of cell spacing and distribution of intermetallic fibers on the mechanical properties of hypoeutectic Al–Fe alloys

The aim of the present investigation was to contribute to provide a basis for understanding how to control solidification parameters, microstructure and mechanical strength of Al–Fe alloys. Upward directional solidification experiments have been carried-out with commercially pure Al and Al–0.5 wt.% Fe, Al–1.0 wt.% Fe and Al–1.5 wt.% Fe alloys. The tensile tests results have been correlated to cell spacing (λ₁), since cellular growth has prevailed along all obtained Al–Fe castings. The used casting assembly was designed in such way that the heat was extracted only through the water-cooled system at the bottom of the casting. In order to investigate the nature of Al–Fe intermetallic fibers, they were extracted from the aluminum-rich matrix by using a dissolution technique. These fibers were then investigated by SEM-EDAX microscopy. It was found that the ultimate tensile strength, yield tensile strength and elongation increase with decreasing cell spacing. The highest ultimate tensile strength was that obtained for the most refined microstructure, i.e. for the Al–1.5 wt.% Fe alloy sample, where a higher density of eutectic fibers was found distributed in a more homogeneous way along the casting section due to lower cell spacings. In contrast, the elongation was found to decrease with increasing solute content.     

Cr/Al复合合金化Fe_3Si基有序合金及其有序度研究

基于合金化的改性原理,以调整材料的长程有序度为改性思想,采用真空电弧熔炼/热压退火制备了四种Cr/Al复合合金化Fe3Si基有序合金。通过XRD,SEM,EPMA等对合金进行了表征,并采用长程有序参数定量表征了退火得到的有序相的有序程度。结果表明:四种不同成分的有序合金,具有不同的显微组织。随着Si含量降低合金有序度下降,且Cr/Al的复合效应对这一趋势起到了促进作用,使得具有相同Si含量的Fe65Si25Cr5Al5有序合金的有序度低于Fe3Si,分别为0.658和0.796。     

Thin wall tubes with Fe3Al/SS316L graded structure obtained by using laser engineered net shaping technology

In the present paper, designing, technological and material aspects of the Laser Engineered Net Shaping (LENS) manufacturing process of functionally graded materials (FGMs) components based on the Fe–Al intermetallic alloys, have been described in details. The presented results are divided into two parts as follows: in the first part a model and a LENS manufacturing process of the selected FGMs component (the Fe₃Al/314L steel tube) have been developed. In the second part, an experimental verification of the model and the process has been carried out. It is shown that, automatically generated code does not allow programming variation of the chemical composition perpendicularly to the wall of the tube. However, applied modification of the code results in a successive direct fabrication of the 316L/Fe₃Al FGM tubes. Directly fabricated FGM tubes were characterized by a smooth transition between both components (the 316L steel and the Fe₃Al alloy), a high metallurgical quality and a good reproduction of the designed model’s shape.