固溶处理对铸造Al-Si-Cu-Mg合金组织与性能的影响

对固溶处理过程中铸造Al-Si-Cu-Mg合金析出相溶解过程进行了研究。结果表明:在固溶处理初期,组织中θ相的数量逐渐减少,但在(FeMn)3SiAl12相中还有一定的Cu含量;而固溶后期,富铁相中的Cu含量也明显降低,且难溶的Al3Ti针状相也发生钝化,但部分Q相尚存在;随着固溶时间的延长,合金基体中Cu和Mg的含量逐渐增多,且富Mn和富Ti相也在合金基体中略有溶解;合金的固溶强化作用主要来源于富Cu相的溶解。在Al-Si-Cu-Mg固溶处理过程中,合金力学性能的提高主要来源于共晶硅相形貌的改善、析出相溶解引起的固溶强化及组织的均匀化。     

Effects of solution heat treatment on corrosion resistance of 5083F Al alloy

Aluminum alloys are used as substitutes for fiber reinforced polymer(FRP) in ships and boats. However, ships constructed with 5000-series Al alloy suffer a little corrosion in the marine environment, when they run in high speed, and high flow rate, etc. Therefore, solution heat treatment was carried out to prevent corrosion. The optimal heat treatment involved heating specimens for 120 min at 420 °C and then cooling them in water. In addition, the optimal ageing condition involved ageing specimens for 240 min at 180 °C. The slow strain rate test(SSRT) in a seawater revealed that heat treatment under optimal conditions produced improved elongation, time-to-fracture and amount of dimples compared with the as-received specimen.     

Evolution of eutectic structures in Al-Zn-Mg-Cu alloys during heat treatment

1 Introduction The solute redistribution during solidification leads to microsegregation and the formation of coarse intermetallic particles, which can significantly influence the properties and productivity of the 7000 series aluminium alloys[1]. In ord…     

Viscosity of In and In-Sballoys

The dynamic viscosity of pure In, In-1%Sb (mass fraction, so as the follows) alloy, In-55%Sb hypoeutectic alloy and In-69.5%Sb eutectic alloy was measured by using a torsional oscillation viscometer at different temperatures above liq-uidus. The experimental results show that the viscosity of these melts decreases with increasing temperature. The anomalous change of viscosity occurs at about 430 and 470℃in pure In melt. The variation of viscosity with temperature well meets exponential correlation and no anomalous change occurs in measured temperature range in the In-1%Sb alloy melt. A transition occurs at about 800℃ in both of In-55%Sb and In-69.5%Sb alloy melts. The sudden change of viscosity suggests the structure change of melts. DSC (differential scanning calorimetry) curves of In-1%Sb alloy during heating and cooling were measured, and the results show that no structural variation in In-1%Sb alloy melt was testified further. In addition, the viscosity of In melt decreases with the addition of1%S     

Al-Mg-Si-(Cu)铝合金在连续升温中的析出行为

采用差示扫描量热法(DSC)研究了Al-Mg-Si和Al-Mg-Si-Cu铝合金的连续升温时效析出行为,并结合JMA方程分析Cu对该合金时效析出动力学的影响,计算出各种亚稳相析出动力学参数,进而得出各相析出的相关动力学表达式及TTT曲线.结果表明:Cu显著地提高了Al-Mg-Si合金的时效硬化效果和速率,这与Cu的添加...     

Effect of heat treatment on eutectic silicon morphology and mechanical property of Al-Si-Cu-Mg cast alloys

1　INTRODUCTIONCastAl Sibasealloysareoneofthemostimpor tantaluminumalloysattributedtotheirlowdensity ,highspecificstrength ,excellentcasting properties ,mechanicalpropertiesanderosionresistance .TheseAl Sialloysaremainlyappliedinautomotive ,aerospace ,transportationandmechanicalindustry ,etc[1,2 ] .The propertiesofalloyscanbeimprovedthroughaddingCuandMgelementsintothealloys .Inthe processofsolutiontreatment ,alloyingele mentscompletelydissolveandformsupersaturatedsolidsolution .However…     

固溶处理对高纯7055铝合金组织的影响

采用光学显微镜(OM)、扫描电镜(SEM)和X射线衍射谱仪研究了固溶处理对高纯7055铝合金组织的影响。结果表明:合金固溶时,粗大的初生AlZnMgCu相溶解缓慢,并逐渐球化;而初生AlZnMgCuFeTi相几乎不溶解。固溶温度越高(460-480℃),时间越长(0-240min),初生AlZnMgCu相溶解越多,再结晶越多,晶粒尺寸越大。再结晶主要于初始晶界上的粗大初生相上形核(PSN机制),并向弥散Al3Zr粒子少的变形晶粒内部长大。490℃固溶时,出现过烧组织,晶粒粗大。分级固溶较单级固溶可更好的控制合金组织,如460℃×120min 480℃×60min与480℃×180min相比,再结晶和晶粒尺寸小得多,但初生AlZnMgCu相溶解程度相差不大。     

NiZr和NiZr_2共晶温度的测定

有关Ni-Zr二元系中化合物NiZr和NiZr2之间的共晶温度,在热力学计算结果和实验数据之间存在较大差异,对此本文进行了针对性实验测定。利用氩气保护电弧熔炼,在NiZr和NiZr2成分范围内,制备了65wt%、68wt%、72wt%和74wt%Zr的Ni-Zr合金。选用商用氧化铝坩埚和自制氧化锆坩埚,以不同加热速率分别进行了差示扫描量热(DSC)测量,最终确定该共晶温度为1022±5℃。同时对实验合金与坩埚的反应情况进行了热力学分析,证实在测量温度范围内(<1100℃)采用氧化铝坩埚进行相关实验的适用性;在1170℃,氧化锆本身存在由单斜向四方的同素异构转变,氧化锆坩埚适用于该温度以下含锆合金的相平衡与热力学测量。     

Strengthening-toughening of 7xxx series high strength aluminum alloys by heat treatment

1　INTRODUCTIONAerospaceand groundtransportationvehicleswithreducingstructuralmasscanenhancecarrycapa bilityandflexibility ,decreasefuelconsumption ,andextendflightvoyageevidently .Highstrengthstruc turalmaterialswithlightdensityplayapivotalroleonreducingmassinstructure .Presently ,confrontedwithcompetitionofresinbasedcomposites ,alu minumalloysas primarystructuralmaterialsforspacecraftandgroundtransportationvehiclesarede velopinginlinesofsuperhighstrength ,corrosionen durance ,lowdensitya…     

热处理工艺对6061铝合金筒形件旋压过程及其性能影响

为满足某6061铝合金筒形件产品较高的形状、尺寸精度及机械性能要求,对热挤压态6061铝合金管坯件旋前不同热处理工艺规范(退火、固溶、不完全退火和半同溶)进行了分析比较,研究获得不同热处理工艺规范对旋压成形过程及其性能的影响规律.结果表明,对热挤压态6061铝合金管坯件而言,在旋压成形前进行半固溶处理(即将管坯加热到4...     

Optimization of heat treatment of gravity cast Sr-modified B356 aluminum alloy

In recent years, certain foundry processes have made it possible to obtain products with very thin parts, below the 4 mm threshold of the permanent mold casting technology. The safety margins of these castings have been reduced, so the T6 heat treatment conditions adopted for the Al–7Si–Mg alloys need to be investigated to identify the best combination of strength and ductility. Furthermore, the cost and the production time associated with T6 heat treatment have to be optimized. In the present work, an experimental study was carried out to optimize the solution treatment and artificial aging conditions in gravity cast thin bars of B356 aluminum alloy modified with Sr. Two solution temperatures were selected, 530 °C and 550 °C, respectively, with solution time ranging from 2 to 8 h, followed by water quenching and artificial aging at 165 °C with aging time from 2 to 32 h. The results of hardness and tensile tests were correlated with differential scanning calorimetry (DSC) analysis. The best combination of mechanical properties and heat treatment duration was obtained with 2 h solutionizing at 550 °C and 8 h aging at 165 °C. DSC analysis showed that the alloy's mechanical properties reach the maximum value when the β″ phase is completely developed during the artificial aging.     

7075和2024铝合金的固溶组织与力学性能

研究了升温固溶处理对提高７０７５和２０２４铝合金的结晶相固溶程度和力学性能的影响,升温固溶可使最终固溶温度超过多相共晶温度而不产生过烧组织,提高结晶相固溶程度。７０７５合金的结晶相较２０２４合金的易于固溶,两种合金的力学性能与固溶程度密切相关。强化固溶的７０７５合金强度提高约２０％,断裂和屈服强度可达６６０ＭＰａ和６０６ＭＰａ,其性能提高的幅度大于强化固溶的２０２４合金。     

DIFFERENTIAL SCANNING CALORIMETRY AND X-RAY DIFFRACTION STUDIES ON AGING BEHAVIOR OF Zn-Al ALLOYS

1. IntroductionZinc-based Al alloys have been widely used in metallurgical, mechanical, mineral andother industry due to their excellent castability, wear and friction .esistancell]. The remarkable success has been gained in substituting for Al alloys as wear and friction alloy.However, one of the shortage for Zn-Al alloys is their poor structure stability, which meansthat the transformation would occur when working so that as-cast alloy would not be usedin harsh working condition. The suita…     

Influence of Si content and heat treatment on microstructure of Al-Fe-Si alloys

The effect of Si addition and heat treatment on the Al-5wt.%Fe al oy has been investigated by OM, SEM-EDS and XRD. The results show that the Si plays a significant role in refining the primary Al3Fe phase. It was found that the addition of 3.0wt.% Si made the al oy present the finest and wel -distributed primary Al3Fe phase, but the Al3Fe phase almost disappeared when 5wt.% Si was added. With further increase in the Si content, some Fe-rich phases appeared in the inter-grains and coarsened. In addition, the heat treatments exert a significant impact on the microstructural evolution of the Al-5wt.%Fe-5wt.%Si al oy. After heat treatment for 28 hours at 590 oC, the coarse platelet or blocky Fe-rich phase in Al-5wt.%Fe-5wt.%Si al oys was granulated; the phase transformation from metastable platelet Al3FeSi and blocky Al8Fe2Si to stable Al5FeSi had occurred. With the extension of heat treatment, the Si phase coarsened gradual y.     

真空压铸对Al-Si-Cu合金固溶过程共晶硅的影响

对真空压铸Al-Si-Cu合金试样（500 mbar）和普通压铸Al-Si-Cu合金试样在500 ℃固溶处理0.5、2、4、6 h后,利用光学显微镜及相应软件研究了固溶处理过程共晶硅形貌的变化。结果表明：真空压铸可以得到更加细化的铸态共晶硅颗粒;在固溶处理过程中,真空压铸试样也可以得到球化效果更好的共晶硅颗粒,并在固溶处理4 h时达到最佳。     

Al-Zn-Mg-Cu合金厚板固溶热处理工艺研究

研究了不同固溶热处理工艺对Al-Zn-Mg-Cu合金时效厚板力学性能、电导率、耐蚀性能的影响.同时借助于光学金相显微镜、扫描电镜和透射电镜等分析手段对合金的微观组织进行观察,并结合试验数据进行分析,确定合理的固溶热处理工艺.     

Effects of heat treatment on mechanical and tribological properties of cobalt-base tribaloy alloys

Cobalt-base Tribaloy alloys are important wear-resistant materials, especially for high-temperature applications, because of the outstanding properties of the strengthened cobalt solid solution and the hard Laves intermetallic phase that make up the alloys. The Laves intermetallic phase is so abundant (35–70 vol.%) in these alloys that its presence governs all of the material properties. Heat treatment may alter the volume fraction, the size/shape, and the distribution of the Laves phase in the microstructures as well as the phase and structure of the cobalt solid solution, thus influencing the mechanical and tribological properties of the alloys. In this work, the effects of heat treatment on two cobalt-based Tribaloy alloys, T-400 and T-200, were studied. The former is a well-known Tribaloy alloy, and the latter is a newly developed one. These two alloys were heat treated in different conditions. The phases and microstructures of the alloys before and after the heat treatments were analyzed using x-ray and scanning electron microscopy. The mechanical and tribological properties of the alloys were investigated using a nano-indentation technique and a pin-on-disc tribometer, respectively.     

Electrochemical impedance spectroscopy analysis on aluminum alloys in EXCO solution

Electrochemical impedance spectroscopy (EIS) of Al‐Zn‐Mg‐Cu alloy in EXCO solution has been investigated. The results show that the impedance spectroscopy of the investigated electrode consists of two capacitive loops in the high and middle frequency domain respectively and an inductive loop in the low frequency domain at the first 30 h of immersion; the inductive arc disappears between 30 h and 60 h while it takes on at the low frequency domain at the last 36 h of the immersion time. A model based on the corrosion mechanism of the aluminum alloy and corroding morphology was proposed and applied to analyze the EIS results.