CuCr50合金的快速凝固

采用单辊旋铸法研究了CuCr50合金的快速凝固规律,并进行了实验分析.结果表明:高温下CuCr50合金与石英坩埚发生反应,CuCr50合金受到污染;单辊旋铸的CuCr50合金快速凝固时发生了液相分离.     

快速凝固Al-Si-Ti-Pb合金中Pb的沉淀特征

本文研究了快速凝固Al-Si-Ti-Pb合金中Pb的沉淀特征。在冷却速度达5～6×10~5K/s的合金条带中,透射电子显微镜(TEM)分析表明合金元素Si、Ti基本上已超固溶于α-Al基体内部,而唯有细小的Pb相颗粒仍偏聚在α-Al的微细胞晶边界,并且同α-Al基体之间保持有严格的位向关系,在电子衍射中呈现出别致有趣的双衍射花样。这些工作加深了对Pb在合金凝固过程中所具特性的认识。     

6061合金吊钩时效强化工艺研究

研究了实际生产中的时效热处理工艺对6061合金吊钩强度的影响,对产品采用机械加工后直接人工时效及先固溶再时效的两类时效工艺;测定了强度及硬度值;用光学显微镜和透射电子显微镜进行了显微组织观察;比较了不同时效工艺的试样在性能和组织方面的变化;提出了相对较为经济有效的时效强化工艺．     

快速凝固Cu—Cr合金导电性分析

分析了快速凝固和常规固溶处理后,Ｃｕ－０．８Ｃｒ合金导电性的差异及时效处理对合金导电性的影响。结果表明：快速凝固合金中过饱的Ｃｒ原子是造成电阻率高的主要原因,晶体缺陷对电阻率的影响很小。时效过程中导电率的恢复是由Ｃｒ原子的析出并产生较大间距的Ｃｒ相所致。     

Fe-Sn-Si偏晶合金的快速凝固研究

在落管中对Fe60.4Sn29.6Si10、Fe43.6Sn21.4Si35和Fe20.1Sn9.9Si70三元偏晶合金进行了无容器快速凝固实验。3种合金液滴的直径范围为100~1 000μm的液滴,凝固组织都呈现2层或3层壳核组织以及第2相弥散分布的凝固组织。XRD、EDS及SEM分析表明,Fe60.4Sn29.6Si10合金液滴的凝固组织由α-Fe、β-Sn、FeSi和FeSn组成;Fe43.6Sn21.4Si35合金液滴的凝固组织由β-Sn、FeSn2、FeSi和Fe2Si组成;Fe20.1Sn9.9Si70合金液滴的凝固组织由β-Sn、FeSi2和Si组成。     

快速凝固条件下Cu-Cr合金的液相分解

采用快速凝固方法研究了Cu100-xCrx(x=2，25和35％)合金凝固行为．利用带有能谱(EDS)的扫描电子显微镜(SEM)分析了Cu—Cr合金的显微组织形貌和成分．实验结果证实，Cu—Cr合金在快速凝固过程中发生了液相分解，在较大的富Cr液相分解球中可观察到来自于二次相分解的、更细小的富Cu粒子．与Cu—Co和Cu-Fe液相分解组织不同，快速凝固Cu-Cr合金的大尺寸液相分解球不是由相互表面界限明确的、尺寸更小的液相分解球所组成，而是一个整体结构．     

快速凝固 Al-Fe 合金中准晶相的研究

在快速凝固Ａｌ－Ｆｅ－Ｖ－Ｓｉ合金棒材中发现了１种圆形准晶相,尺寸为０２～０５μｍ,成分为Ａｌ－８０ａｔ％Ｆｅ－２．１ａｔ％Ｖ－３．２ａｔ％Ｓｉ。对此准晶进行了透射电镜、Ｘ－光衍射结构分析,并对准晶的形成机制进行了讨论。     

快速凝固Al-Fe合金的显微组织及其对性能的影响

本文用分析电子显微术(AEM)和力学性能测试研究了快速凝固热强合金Al-Fe-(Ce、Ti、Zr)的显微组织及其对高温性能的影响。首先分析了急冷条带的凝固过程动力学及凝固速度对胞晶内部溶质分布的影响,之后对急冷条带及热挤合金的退火过程与弥散相分布时合金高温性能的作用进行了研究。分析结果表明:影响合金凝固过程的主要是初始过冷度和凝固速率;胞晶内溶质元素固溶量随凝固速度增大而升高。合金高温性能主要同弥散相的结构及分布有关。     

快速凝固FGH95合金粉末的非平衡溶质分配

测定了用等离子旋转电极雾化工艺方法生产的FGH95合金粉末颗粒的枝晶偏析,并运用显热容法计算了合金粉末颗粒快速凝固过程中的非平衡溶质分配系数．结果表明：FGH95合金粉末颗粒枝晶间富Mo、Nb、Ti元素而贫Ni、Co、W元素;随着粉末颗粒尺寸的减小,溶质分配系数远离平衡值的程度增大,枝晶偏析也明显减小．     

The Rapidly Solidified Aging Copper Alloy by BP Neural Network

1　IntroductionTheCu Cr Zralloysarewidelyusedinavarietyofproductsrequiringacombinationofhighmechanicalprop ertiesandgoodelectricalconductivity .Examplesincludeelectronicconnectors ,integratedcircuitleadframesandweldingelectrodetips[1-4] .Howeveritisdifficulttofur therimprovetheirelectricalandmechanicalpropertiesun derconventionalsolutionheat treatment (CSHT)sincethedegreeofprecipitationhardeninguponagingisre strictedbythelimitedsolubilityofchromiumandzirconi umincopper.Inanefforttoimproveth…     

Devitrification process in rapidly solidified Al-Ni-Cu-Nd metallic glass

In the present study, rapidly solidified ribbons of A187 Ni7 Cu3 Nd3 metallic glass was prepared by using melt spinning. Devitrification process of the totally amorphous ribbons was investigated by high temperature X-ray diffraction analysis, combining with differential scanning calorimetry, under continuous and isothermal heating regime. The X-ray diffraction intensity and full width at the half maximum (FWHM) were analyzed to investigate the increase of crystallized amount and growth of α-Al crystal particles. The results show that under continuous heating regime, the metallic glass devitrifies via two main stages: primary crystallization, resulting in two-phase mixture of α-Al plus residual amorphous phase, and secondary crystallization, corresponding to rapid precipitation of some inter-metallic phases in the form of dispersion or eutectic mixture. Under isothermal heating regime, only Al crystal precipitates from the Al-rich amorphous matrix at low temperature, and when heating at 280 ℃ only Al     

Second phases of rapidly solidified AlFeCrZrVSi alloy and their thermal stabilities

ＳＥＣＯＮＤＰＨＡＳＥＳＯＦＲＡＰＩＤＬＹＳＯＬＩＤＩＦＩＥＤＡｌＦｅＣｒＺｒＶＳｉＡＬＬＯＹＡＮＤＴＨＥＩＲＴＨＥＲＭＡＬＳＴＡＢＩＬＩＴＩＥＳＸｉａｏＹｕｄｅＬｉＳｏｎｇｒｕｉＬｉＷｅｎｘｉａｎＺｅｎｇＺｈｉｈｕａＭａＺｈｅｎｇｑｉｎｇ（Ｄｅｐａ...     

Transient spinodal decomposition during annealing of rapidly solidified Al-10Sr alloy

Rapidly solidified Al-10Sr alloy ribbons were prepared using a single roller melt spinning technique. The annealing process of the rapidly solidified Al-10Sr alloy has been carried out using differential scanning calorimetry (DSC). The microstructure of as-annealed Al-10Sr alloy has been characterized by transmission electron microscopy (TEM). The equilibrium AUSr phase is dominant in the as-annealed alloy. Besides the Al4Sr phase, an AlSr phase is also found in the alloy isothermally annealed at 873 K for 90 min. Furthermore, a modulated nanostructure was observed in the alloy isothermally annealed at 873 K for 90 min. With further prolonged annealing time, however, the AlSr phase disappears in the as-annealed alloy. The dependence of particle size and growth rate on annealing time as well as the modulated structure shows that the occurrence of the AlSr phase may be due to the spinodal decomposition.     

Effects of aging parameters on hardness and electrical conductivity of Cu-Cr-Sn-Zn alloy by artificial neural network

In order to predict and control the properties of Cu-Cr-Sn-Zn alloy, a model of aging processes via an artificial neural network (ANN) method to map the non-linear relationship between parameters of aging process and the hardness and electrical conductivity properties of the Cu-Cr-Sn-Zn alloy was set up. The results show that the ANN model is a very useful and accurate tool for the property analysis and prediction of aging Cu-Cr-Sn-Zn alloy. Aged at 470–510 °C for 4-1 h, the optimal combinations of hardness 110–117 (HV) and electrical conductivity 40.6–37.7 S/m are available respectively.     

快凝PM Al—Li合金高应变速率超塑性变形机制

对PM－Al-Li合金在高应变速率超塑性变形行为进行了研究,对其变形机制进行了讨论,研究表明,PM－Li合金在超塑变形过程中晶粒会发生形变诱发动态长大,其长大速率主要受应变速率所控制;在变形过程中,随着就变速率的增加,晶界滑动的协调机制由晶内位错滑移协调逐步向晶粒变形协调转变;PM－Al-Li合金在570℃以上变形时,绝热加热现象的发生会导致液相的产生,并且液相的体积分数随应速率的增加而增大,合金的延伸率随着液相体积分数的增加而急剧下降。     

Zn在AlSiCuMg合金时效过程中的作用

研究了微量合金元素Zn对高强度铸造合金Al-Si-Cu-Mg时效过程的影响.通过差热分析和透射电镜等分析测试方法表明：当锌的添加量在w(Zn)=0.1%～1.0%时，可提高合金的时效峰硬度，加快合金的硬化速度.当Zn含量为0.5%时，合金的时效峰最高，当Zn含量增大到w(Zn)=1%时，硬度有所降低，但仍高于无Zn合金.通过DSC和TEM分析显示，微量的Zn固溶于基体中，加快了亚稳相的析出，较早地形成了细小而密集的亚稳相，从而使合金获得了较高的峰时效硬度.     

Microstructure and mechanical properties of rapidly solidified Al-Cr alloys

The microstructure and mechanical properties of rapidly solidified Al-Cr alloys were investigated by XRD, TEM and microhardness testing instrument. The results indicate that the matrix of rapidly solidified Al-Cr alloys is α-Al solid solution when the Cr content is lower than 4 wt%. However, when the Cr content is above 4 wt%, the microstructures of rapidly solidified Al-Cr alloys are different along cross section. The microstructure of alloy contacting copper roller consists of α-Al and a few intermetallic compounds. With the increase of distance from copper roller, the matrix consists of α-Al and spherical intermetallic compounds which conglomerate in α-Al matrix. These intermetallic compounds are Al₇Cr, Al₁₁Cr and Al₄Cr. The tensile strength has the maximal value when the Cr content is about 8 wt%. The annealed microstructures show that supersaturated α-Al solid solution dissolved with increasing anneal temperature. The starting temperature of the second phase precipitated from the supersaturated α-Al solid solution desponds on the supersaturation. Meanwhile, the microhardness of rapidly solidified Al-Cr alloy reaches maximal value after annealing at 300 °C. Funded by the Innovation Fund for Outstanding Scholar of Henan Province (No. 0621000700)     

时效处理铝合金RR350显微组织分析

经研究分析,铸造铝合金RR350经淬火时效后,其主要合金相由细小初生相(α+θ")、二次相TMn和TNi、过剩相AlCuNi、Al9FeNi以及NiAl3、TiAl3等相组成.这些合金相大多以复合相形式分布于晶界上,阻止晶界的扩展.结果表明,采用成分多元少量、合金相复合多样,合理分布于铝合金中,可提高铸造铝合金RR350的热强性、耐蚀性等性能.