铝锂合金2090-T83的合金化研究

以航空用铝锂合金2090-T83为研究对象,研究了合金化过程中Cu、Zn、Mn、Mg、Zr、In、Cd、Ge、Ag、Ce、La、Y和Sc等元素对合金强度、塑韧性、强化作用、腐蚀性能、焊接性及各向异性的影响及Ag、Mg元素对合金时效硬化的影响。结果表明:Cu、Zr、Ge、Sc、Ce、La和Y元素影响合金强度及塑韧性,Zn、Sc元素影响合金的腐蚀性能,Mn、Ce、La、Y元素影响合金各向异性,Mg、Ag、In、Cd元素影响合金的强化性能,Sc元素影响合金焊接性及热裂纹敏感性,Ag元素对合金时效强化效应很小,Mg元素对时效强化效应较大,Ag和Mg两元素结合对合金时效强化效应很大。     

合金元素对6063铝合金组织性能的影响

以Al-Mg-Si系6063铝合金为研究对象，采用试验的方法研究了主要合金元素Mg、Si和杂质元素Fe,Zn对合金组织性能的影响，并在分析作用机理的基础上给出了改善材料性能的合理化建议。研究表明，主要合金元素Mg、Si对材料的强度和腐蚀性能有重要影响，生产实际中应使二者质量之比略小于正常值1．73；杂质元素Fe、Zn对合金组织的稳定性有一定影响，一般会使制品表面出现不同程度的点缺陷。     

合金元素对Al-Mg-Si系铝合金组织及性能的影响

以Al—Mg-Si系合金材料为研究对象，实验研究了主要合金元素Mg、Si和杂质元素Fe、Zn对合金组织及性能的影响，并在分析作用机理的基础上给出了改善材料性能的合理化建议。研究表明：主要合金元素Mg、Si对材料的强度和腐蚀性能有重要影响，生产实际中应使二者质量之比略小于正常值1．73；杂质元素Fe、Zn对合金组织的稳定性有一定影响，一般会使制品表面出现不同程度的点缺陷。     

合金化对Al-7.5Si-0.35Mg铝合金性能的影响

在铝硅镁合金中添加Cu、Ni、Mn、Fe元素,研究了合金元素对合金力学性能的影响。结果表明:加入1%Cu、0.7%Ni、0.5%Mn、0.9%Fe的Al-7.5Si-0.35Mg合金性能较佳;Ni对Al-7.5Si-0.35Mg合金常温抗拉强度影响最大,Cu对合金高温抗拉强度影响最大。     

TiNi基形状记忆合金合金化研究进展

综述了近年来在TiNi基形状记忆合金中添加的合金元素种类,以及各种合金元素对TiNi基形状记忆合金性能的影响。分析了加入Cu、Cr、Ce、Hf、Pd、Co和Al合金元素对材料相变、形状记忆效应和超弹性的影响,提出了该研究领域今后的研究重点和需进一步解决的问题。     

合金化元素对Nb-Si基超高温合金微观组织和性能的影响

Ti、B、Al和Cr等元素对Nb-Si基合金组织和性能影响的研究和报道较多,而对Zr、Mo、W和Hf等元素的研究报道较少,这些元素的加入不仅能够优化Nb-Si基合金的微观组织,也能使合金的综合性能明显提升。系统的分析和归纳这些合金元素的加入对Nb-Si基合金组织和性能的影响,对今后Nb-Si基超高温合金的设计和应用有着重大的意义。本文重点关注了Zr、Mo、W和Hf等合金元素对Nb-Si基合金组织、力学性能和高温抗氧化性能的影响。     

硅、锰对铸态ZA-27合金组织性能的影响

采用正交组合回归设计试验方法,研究了硅、锰元素对铸态ZA-27合金力学性能的影响规律,分析了硅、锰元素对合金组织的影响。研究结果表明,硅、锰元素对ZA-27合金的室温硬度、100℃硬度、抗压强度和冲击韧性都有显著影响。适当控制硅、锰含量,并加入稀土元素进行变质处理,可得到具有较高强韧性的耐磨锌合金。     

Recent Development of Effect Mechanism of Alloying Elements in Titanium Alloy Design

钛合金的性能主要取决于合金成分和显微组织两方面,而合金元素的种类选择以及添加量是合金成分设计的主要组成内容,不同合金元素的添加可以一定程度上改善合金的强度,高温性能,蠕变性能以及加工性能等,满足特殊工业需求。主要探讨了合金元素在钛合金设计中的作用以及说明了各合金元素在新合金设计中应注意的一些原则,并对合金元素在钛合金设计中存在的一些问题进行探讨和归纳总结,特别对于合金中不同合金元素之间的相互作用,引起合金组织中位错取向和相组成发生变化,从而影响合金的机械性能。另外,对几种经典合金的合金组成、稳定性以及组织性能之间的相互关联进行研究,希望进一步了解合金元素在钛合金中的影响机理,为新型钛合金设计与研发提供参考。     

铸造铝硅合金及其热处理工艺的研究与进展

概述了铸造铝硅合金及合金元素对其组织和性能的影响,介绍了固溶处理、时效处理等热处理工艺的特点、原理及其对铝硅合金组织与性能的影响.指出了现阶段合金元素的调控及热处理存在的不足以及实际应用中存在的问题,同时提出了未来合金元素调控和热处理工艺研究改进的方向.     

钛对2618合金组织及性能的影响

研究了钛元素加入量对2618合金组织性能的影响。结果表明,钛元素作为合金化元素能稍微细化2618合金的铸态晶粒组织,但对Al9FeNi相形态没有影响;钛元素的加入可明显提高250℃×100h热暴露前后的2618合金在250℃高温瞬时强度,但当钛元素加入量大于0.5%后,降低2618合金的室温抗拉强度。     

Heat treatment-modulated coupling effect of multi-scale second-phase particles on the ductile fracture of aged aluminum alloys

Experiments and multi-scale modeling were carried out in order to study the heat treatment-modulated coupling effect of multi-scale second-phase particles on the ductile fracture of two typical kinds of heat-treatable aluminum alloys, i.e. an Al–Cu–Mg alloy and an Al–Mg–Si alloy. It was revealed experimentally and theoretically that an appropriate combination of the multi-scale second-phase particles, which could be achieved by appropriate cooperation of the heat treatment steps, i.e. the solution, quenching and aging treatments, is necessary and sufficient for obtaining an excellent fracture toughness for the heat-treatable aluminum alloys. The experimental phenomenon, that the alloys containing more detrimental constituents but aged at a somewhat higher temperature exhibit ductility and fracture toughness superior to those of the alloys containing less detrimental constituents but aged at lower temperatures, could be reasonably explained by the cooperative effect of the heat treatment steps. Contours of the fracture toughness with respect to the technological parameters of the heat treatment, e.g. the aging temperature and quench factor, were developed to show the cooperative effect of the heat treatment steps on the fracture toughness of the aged aluminum alloys quantitatively. The good agreement between the calculations and the experimental results indicated that the present modeling is applicable for describing the heat treatment-modulated coupling effect of the multi-scale second-phase particles in aged aluminum alloys.     

Enhancement of formability of aluminum alloys in multi-stage forming operations by a local intermediate heat treatment

Within this paper a new approach to enhance the formability of aluminum alloys in multi-stage forming processes will be presented. The technology??s key idea is the local adaption of the mechanical properties after a first forming step and their optimization for the subsequent forming operation. The partial change of the mechanical properties is obtained by a short term heat treatment between two forming steps. Based on the new property distribution the material flow during the second forming is improved and the formability of the material can be enhanced. The presented work covers all necessary steps for a successful application of the technology. After a material characterization in dependency of the pre-straining and the heat treatment, the heat affected zone, which is a result of the high heat conductivity of aluminum alloys was analyzed. In the end appropriate heat treatment layouts were designed via numerical simulation and the enhancement of formability was demonstrated with a real multi-stage forming process.     

Development of thermophysical calculator for stainless steel casting alloys by using CALPHAD approach

The calculation of thermophysical properties of stainless steel castings and its application to casting simulation is discussed. It is considered that accurate thermophysical properties of the casting alloys are necessary for the valid simulation of the casting processes. Although previous thermophysical calculation software requires a specific knowledge of thermodynamics, the calculation method proposed in the present study does not require any special knowledge of thermodynamics, but only the information of compositions of the alloy. The proposed calculator is based on the CALPHAD approach for modeling of multi-component alloys, especial y in stainless steels. The calculator proposed in the present study can calculate thermophysical properties of eight-component systems on an iron base alloy (Fe-C-Si-Cr-Mn-Ni-Cu-Mo), and several Korean standard stainless steel alloys were calculated and discussed. The calculator can evaluate the thermophysical properties of the alloys such as density, heat capacity, enthalpy, latent heat, etc, based on full Gibbs energy for each phase. It is expected the proposed method can help casting experts to devise the casting design and its process easily in the field of not only stainless steels but also other alloy systems such as aluminum, copper, zinc, etc.     

Prediction of residual stress and distortion of ferrous and non-ferrous metals: Current status and future developments

The quantitative prediction of the consequences of a heat treatment, in terms of microstructure and hardness, residual stresses and distortions, implies a thorough knowledge of the coupled thermal, metallurgical, and mechanical phenomena that occur during the treatment and their modeling. Recent progress made in that field for metallic alloys (steels, aluminum alloys, and titanium alloys) is reviewed through different examples.     

The recycling of standard quality wrought aluminum alloys from low-grade contaminated scrap

In recent decades an increasingly large fraction of the world’s wrought aluminum alloys supply has come from the aluminum scrap recovered from industrial waste and discarded post-consumer items. However, replacing even a minor part of primary aluminum in wrought alloys with recycled counterpart originated from lower grades of scrap (typically scrap contaminated with various non-metallic impurities) without influencing the quality of the allay is very demanding from a metallurgical point of view. This article discusses the two approaches for achieving the requested chemical composition of wrought alloys made from recycled aluminum: (i) before melting, by combining the appropriate qualities and quantities of scrap, primary aluminum, and the alloying elements and (ii) during melting, by diluting impurity content with primary aluminum to the needed level and adding, at the same time, the necessary amount of alloying elements for achieving their standard concentration in diluted melts.     

固溶热处理对AA7085铝合金组织与性能的影响

采用拉伸试验、电导率测试、剥落腐蚀试验、金相观察及透射电镜分析等方法,研究了不同固溶热处理工艺(包括常规固溶、高温预析出固溶与部分重固溶)对AA7085铝合金的强度、剥落腐蚀性能及显微组织的影响。结果表明,采用部分重固溶工艺并时效处理后,合金的抗拉强度降低,但电导率与抗剥落腐蚀性能明显得到提高。其原因是通过部分重固溶处理并时效处理后,合金中的晶界析出细小且非连续分布的η析出相,从而提高了AA7085铝合金的抗腐蚀性能。     

6xxx系铝合金表面腐蚀及其防腐的研究现状

6xxx系(Al-Mg-Si)铝合金作为综合性能良好的中强铝合金,因其较小的密度、良好的耐蚀性和成形性等优点,被广泛应用在航空航天、交通运输和建筑机械等领域。然而,该类铝合金在工业应用中依然存在腐蚀问题,造成巨大的经济损失,带来严重的安全隐患。针对这一问题,首先介绍了6xxx系铝合金的腐蚀类型,总结了影响其耐蚀性的影响因素,重点介绍了合金元素对其耐蚀性的影响。已有的研究结果表明:铝合金中的Mg、Si、Cu、Zn等元素显著影响合金的耐蚀性能,过量Si和Cu元素的添加增加了铝合金的晶间腐蚀敏感性;适当地添加过渡族金属元素及稀土元素,可有效改善铝合金的耐蚀性。随后,分析了提高铝合金耐蚀性能的途径,包括改善热处理工艺、优化合金成分及添加复合物等方法,并介绍了几种典型的表面防腐处理工艺,如阳极氧化技术、微弧氧化技术、化学转化膜技术、电镀及化学镀技术。最后总结了以上防护途径存在的一些问题,并指出了耐蚀铝合金的主要发展方向。     

异种合金惯性摩擦焊的研究现状

文中针对钢与其他合金、铝合金与其他合金、钛合金与其他合金、高温合金与其他合金的惯性摩擦焊的研究现状进行了阐述。主要对惯性摩擦焊的工艺参数选取、端面设计、焊前预热、焊后热处理等研究内容进行了综述。并对异种合金惯性摩擦焊存在的问题进行了分析总结。结果表明,采用合理选择工艺参数、设计不同形状的端面、添加中间过渡层、焊前预热处理、焊后热处理等方法获得强度与母材相当、焊接质量较好的接头。建议在后续的研究中,结合数值模拟对异种合金惯性摩擦焊的工艺参数及端面设计进行优化,对接头的元素分布及新相形成的种类与数量进行调控,对焊接界面金属的流动行为进行深入研究,以获得具有综合性能较好的异种合金惯性摩擦焊接头。     

An inverse approach to the numerical design of the process sequence of tailored heat treated blanks

While in industries lightweight construction gain an increasingly significant role and as weight reduction is often done with aluminum sheets, advanced production technologies have to be developed to be competitive for this evolution. Since steel sheet metal parts cannot be substituted directly with aluminum due to its minor formability, the usage of so called tailored heat treated blanks (THTB) is presented in this work. THTB are locally heat treated aluminum blanks from the 6,000-series alloy which exhibit a specific strength pattern optimized to the forming operation leading to a significantly improved formability for the manufacturing of complex aluminum car body parts. The enhancement of the formability is reached by a local heat treatment before the forming process. Due to the strong interdependency of heat treatment and forming operation, a numerical investigation of the process sequence is a prerequisite for a cost-effective usage of the THTB. An inverse approach on basis of a finite element simulation enables the determination of process parameters for an optimized THTB, thus having an effective and efficient engineering method for this technology. The investigations presented in this paper were carried out within the project CRC 396 B4 “Robust, shortened process sequences for lightweight sheet parts” sponsored by the German Research Foundation (DFG).     

铝合金电阻点焊的形核特点

在铝合金的电阻点焊过程中，由于接触电阻具有随机性和分布不连续的特征，而且铝合金材料本身具有优良的导电、导热能力，这使得其点焊的形核过程具有独特的特点。文中采用数值模拟与试验研究相结合的方法对铝合金点焊形核过程进行了分析研究。研究结果表明，铝合金点焊的形核过程与低碳钢等材料的形核过程显著不同，它可以分为以下三个阶段：随机形核阶段、扩展融合阶段和熔核增厚阶段。文中详细介绍了每个阶段的特点和规律。特别是在工频交流焊接的情况下，前两个阶段一般在第一个半波内就已经完成，因此第一个半波对铝合金点焊的焊接质量起着决定性作用。结合这些特点和规律对铝合金点焊的控制提出了一些有价值的建议。