金属间化合物Ni3Al基合金结构焊工研究

对Ｎｉ３Ａｌ基合金结构焊接的工艺进行了研究，对焊缝显微组织及性能进行了分析，结果表明：采用合理的焊接工艺参数，用Ｎｉ８１８焊条能够实现Ｎｉ３Ａｌ工个的结构焊接。     

Ti3Al金属间化合物超塑性的研究进展

详细的对Ti3Al金属间化合物的超塑性研究进展状况进行了总结和评述.根据现有的研究结果可知,此类合金的最佳超塑性变形温度为940～980℃,最佳超塑性变形的应变速率为10-4～10-3s-1,其最大延伸率可达1500%左右,接近于普通钛合金的超塑性水平.Ti3Al金属间化合物超塑变形的主要机制是晶界滑动,失效的主要原因是空洞的形成和连接.针对已取得的研究成果和在目前研究中仍然存在的问题,提出了一些有关Ti3Al金属间化合物超塑性研究的看法.     

Ni3Al基高温合金不同温度下变形组织的透射电镜观察

本文利用透射电镜对Ni_3Al基高温合金的初始状态、室温和870℃下瞬时拉伸和1100℃持久蠕变试样的微观组织及位错组态进行了观察。结果表明:合金在γ/γ′界面上存在大量网络化的错配位错,这些位错在变形时对基体γ′中的位错运动起强烈的阻碍作用;在1100℃持久蠕变过程中合金组织发生显著变化,γ相聚集回溶成高位错密度的胞状组织,对合金仍起强化作用。γ相是合金的强化相。     

金属间化合物Fe3Al的研究进展

对Fe3Al基合金及其相关领域的研究进展进行了综合评述,主要包括:Fe3Al基合金的制备方法和加工性能的改善、Fe3Al基合金的超塑性变形工艺、Fe3Al基复合材料性能的改善、热处理对Fe3Al基合金的强韧化作用.着重论述了Fe3Al基合金的制备方法、强韧化措施、热处理以及复合材料等研究现状,并介绍了近年来Fe3Al基合金及其复合材料在工程上的一些应用情况.     

Ni3Al金属间化合物多孔材料的制备及抗腐蚀性能

使用粉末冶金模压成形和无压反应烧结方法制备出Ni3Al金属间化合物多孔材料,研究了反应过程中Ni3Al金属间化合物多孔材料的体积膨胀、孔结构参数、组织形貌,以及在KOH溶液中的抗腐蚀性能.结果表明:烧结后Ni3Al金属间化合物多孔材料发生了显著膨胀,最大孔径和开孔隙度都随着温度的升高而升高,当温度到达750℃时体积膨胀...     

溅射CoCrAlY涂层对Ni3Al金属间化合物热腐蚀抗力的影响

采用电化学方法并结合物相分析技术研究了溅射CoCrAlY涂层对Ni_3Al金属间化合物热腐蚀抗力的影响。结果表明,Ni_3Al金属间化合物的耐蚀性能极差,合金表面没有形成Al_2O_3保护膜。CoCrAlY涂层表面形成了富铝氧化膜,明显改善了Ni_3Al金属间化合物的耐蚀性能。     

激光合成Ni_3Al金属间化合物的腐蚀行为

通过激光技术合成单Ni3Al相金属间化合物,利用电化学方法及盐雾试验研究了Ni3Al金属间化合物在Na Cl溶液中的腐蚀行为特征、耐腐蚀性能及腐蚀机理。结果表明:激光合成Ni3Al金属间化合物在不同浓度的Na Cl腐蚀介质中均能形成保护性钝化膜,当Na Cl溶液浓度低于2%时,钝化膜具有良好的稳定性和耐腐蚀性能。当Na Cl溶液浓度高于3.5%时,钝化膜产生活化溶解,稳定性下降,Ni3Al金属间化合物表面形成点蚀坑,并且随腐蚀介质浓度增大,腐蚀加剧。Ni3Al金属间化合物表面点蚀坑边缘规整、腐蚀界限清晰,腐蚀机制为典型的晶内腐蚀,腐蚀过程中未形成应力腐蚀微裂纹等破坏性缺陷,具备在沿海湿热盐雾环境下使用的潜在价值。     

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。     

凝固速度对Ni/Ni3Al基高温合金组织演变及相变行为的影响

Ni/Ni3Al基高温合金因其优异的高温强度、抗氧化性能和抗蠕变能力等优点,被广泛应用于航空航天等领域.简要介绍了凝固速度对Ni/Ni3Al基高温合金中γ′,β相以及碳化物等析出相的组织演变及相变行为的影响,为Ni/Ni3Al基高温合金非平衡凝固的研究开发及组织调控提供借鉴和指导.Ni/Ni3Al基高温合金中γ′,β ...     

Regularities of Formation of Ternary Intermetallic Compound between Transition Elements

Four parameters, phi (electronegativity), n(ws)(1/3) (valence electron density in Wagner-Seitz cell), R (Pauling's metallic radius) and Z (number of valence electrons in atom), and the pattern recognition methods were used to investigate the regularities of formation of ternary intermetallic compounds between three transition elements. The obtained mathematical model expressed by some inequalities can be used as a criterion of ternary compound formation in "unknown" phase diagrams of alloy systems.     

金属间化合物Fe3Si的研究进展

文章简要介绍了金属间化合物Fe3Si的基本性质、常用的制备方法,以及在软磁性能等方面的应用,并对存在的一些问题以及未来可能的研究方向做了简要探讨。     

Electronic Structure Effect on Model Cluster for L1_2 Structure of Al_3Ti Intermetallic Compound with an Addition of Alloying Elements Fe, Ni and Cu

By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.     

复相Al3Ti基合金的高温强化

报导了对Ａｌ３Ｔｉ结合合金进行复相强化的研究,利用适量的Ｎｂ合金化,在Ｌｌ２Ａｌ３Ｔｉ基体中形成分散的第二相,其室温和高温强度显著提高,韧性也有改善。改变制备工艺,使合金发生重有序和析出过程,形成具有高度弥散微粒的复相细晶组织,合金的室温和高温强度进一步提高。并探讨了其强韧化作用机理。     

Structure of the Intermetallic Compound Ni3Al Synthesized under Compression of the Powder Mixture of Pure Elements Part I: Phase Composition and Microstructure of Main Phase

It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of grains has its own domain and dislocation structure. There are mono- and polydomains with and without dislocations. The grains of the main phase of mono- and polydomains without dislocations and polydomains with dislocations were formed by diffusion in the solid phase. In these conditions NiAl3 phase is located on the grain boundary of the main phase. The Ni2Al3 phase is located at the triple joints of the main phase.     

Preparation of Al_3Sc Intermetallic Compound by FFC Method

The FFC Cambridge process is a direct electrodeoxidation process used to reduce metal oxides for metals or alloys in molten salts.Al-Sc compound oxides are used as a precursor which formed upon blending and sintering Al2O3,Sc2O3 and Al powders and are successfully reduced by using the FFC Cambridge process at 973 K with a constant cell voltage of-3.2 V.This method is applied to the preparation of fine Al3Sc particles, which can give another new view for aluminum industry.