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采用3种不同的工艺(直接在450℃下进行时效处理;80%冷轧,然后在450℃下进行时效处理;600℃/8 h高温预时效+80%冷轧+780℃/2 min+450℃/16 h终时效)对固溶处理后的Cu-2.0Ni-0.34Si-Mg合金进行形变热处理,研究形变热处理工艺对该合金的组织与硬度及电导率的影响。结果表明:采用第3种工艺对合金进行形变热处理,由于其中的短时高温预处理可以获得溶质原子充分固溶的过饱和固溶体,因此终时效后的合金具有最佳的综合性能,显微硬度为180 HV,相对电导率为49.8%IACS,伸长率为13%。合金的平均晶粒尺寸约为20μm,主要析出强化相为δ-Ni2Si。 相似文献
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采用单辊急冷快速凝固方法制备了两相钛合金薄带,并对薄带进行高温时效处理,采用X射线衍射(XRD)、环境扫描电子显微镜(ESEM)对所得薄带进行微观研究,发现薄带合金主要是由过饱和β相和α相组成;在960℃下真空时效,发现薄带由均匀的α相和β相组成.薄带合金晶粒尺寸变小,显微硬度上升,很好地验证了Hall-Petch关系. 相似文献
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采用事温水作为淬火介质进行Jominy末端淬火实验,采集了合金淬火过程试样的温度-时间变化曲线,测定了末端淬火试样距淬火端不同距离合金的淬火态电导率和硬度,结合透射电镜组织观察,研究了冷却速率对合金过饱和固溶体脱溶析出的影响,通过观察淬火析出相非均质形核,考察了7050合金过饱和固溶体淬火脱溶析出相的析出规律.结果表明,淬火冷却速率对7050合金的过饱和固溶体的脱溶析出行为有着显著影响.末端淬火实验过程中,合金过饱和固溶体大角晶界、小角晶界、晶内弥散相周围分别在距淬火端5,10和15 mm出现淬火析出相.随着距淬火端距离的增加,淬火态合金导电率呈上升趋势,合金淬火析出相尺寸变大,体积分数增加.合金淬火平衡η相的非均质形核核心的优先次序为:晶界、亚晶界、A国<,3>Zr等纳米级弥散相粒子. 相似文献
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采用熔体快淬的方法研究了Si,Co含量对LaFe13-x-ySixCoy合金凝固行为的影响.应用XRD和SEM分析了合金显微组织、结构和相组成.结果表明:Si,Co含量对合金的凝固行为有很大的影响,当合金中x=0,y=0~0.4时合金显微组织由α—Fe相和La+α-Fe相组成;当x=0.5~1.0,y=0~0.4时合金显微组织由α-Fe相和La(Fe,Co)si相组成;当x=1.0,y=0.6时合金显微组织中出现La(Fe,Co,Si)13相. 相似文献
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钛合金具有相变复杂性以及相变敏感性,制备状态下的高强钛合金其显微组织及力学性能与对应的固溶-时效工艺直接相关。该研究对名义成分为Ti-5Al-5Mo-5V-1Cr-1Fe的TC18钛合金进行固溶-时效处理,对比研究不同固溶温度以及时效温度对其显微组织及力学性能的影响。结果表明,固溶-时效热处理对合金性能提升效果显著,固溶处理使合金基体中残存的初生α相粗化,其他区域形成过饱和固溶体,在接下来的时效过程中,β基体析出细小针状次生α相。在两种α相的配合影响下,合金整体强度提升明显。 相似文献
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应用快速凝固技术制取了Al—4.85Cr—1.60Zr合金的完全过饱和固溶体粉末,经爆炸压实成型。研究了原始粉末爆炸压实试样及时效试样的相组成和脱溶过程,结果表明:爆炸压实后试样仍然保持过饱和固溶体状态,时效时共析出Al_(12)Cr_2和Al_3Zr,先以前者析出为主,随之后者析出占主要地位。在350~450℃时效时合金具有明显的时效硬化效应。 相似文献
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《Acta Metallurgica Materialia》1994,42(5):1541-1549
A new experimental technique for examining dynamic strain ageing in solid solutions is proposed. It is based on the imposition of an oscillatory perturbation on a tensile specimen monotonically deforming under strain or stress control. Experimental measurements on an AlMgSi alloy show that the attendant oscillatory response has characteristic features which may be used to detect and characterize dynamic strain ageing. A constitutive model which accounts for dynamic strain ageing is used to provide a theoretical basis for the analysis. A closed-form solution of the governing equations is obtained under the assumption of small oscillatory perturbations. A full numerical solution is given for the AlMgSi alloy which was tested using the technique proposed. Good agreement of the predictions of the model with the experimental results is obtained. 相似文献
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新型耐蚀铸造铝合金Al-2Mg-3Si热处理制度研究 总被引:5,自引:1,他引:4
主要介绍了不同的固溶和时效处理制度对新型耐蚀铸造铝合金力学性能、耐蚀性能的影响,通过对金相组织观察和能谱分析,结合相图进行了讨论,指出Mg2Si相的充分固溶和均匀析出是决定Al-2Mg-3Si合金综合性能的关键因素,并根据材料实际应用情况最终确定了该新型耐蚀铸铝的热处理制度。 相似文献
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E. V. Dedyaeva P. N. Nikiforov A. G. Padalko G. V. Talanova L. I. Shvorneva 《Russian Metallurgy (Metally)》2016,2016(9):856-863
A binary 12Si–Al alloy is subjected to barothermal treatment (hot isostatic pressing) at a temperature of 560°C and a pressure of 100 MPa for 3 h. This treatment is shown to result in a high degree of homogenization in the chemically and structurally heterogeneous initial alloy. As follows from the morphology of silicon microparticles, barothermal treatment of the 12Si–Al alloy leads to thermodynamically promoted silicon dissolution in the aluminum matrix up to ~10 at % with the formation of a metastable supersaturated solid solution, which decomposes upon cooling. The process of removal of porosity, which results in the formation of a high-density homogeneous material, is analyzed. After a cycle of barothermal treatment, a bimodal size distribution of the silicon phase constituent forms in the 12Si–Al alloy at an average microparticle size of 2.7 μm and an average nanoparticle size of 36 nm. The linear thermal expansion coefficient of the alloy decreases after barothermal treatment, and the microhardness of the eutectic alloy is determined after this treatment. Barothermal treatment of the 12Si–Al alloy is shown to be an effective tool for the removal of microporosity, achieving a high degree of homogenization, and forming a near-optimum bimodal size distribution of the silicon structural constituent, which is comparable with or even exceeds the results of conventional heat treatment of the material at atmospheric or lower pressure. 相似文献
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为满足牙种植体对高强度、低模量钛合金的需要,设计开发了一种具有较低弹性模量和较高强度的新型医用TB12亚稳β钛合金。研究了固溶处理和时效处理对制备的8 mm TB12钛合金热轧棒材力学性能的影响。研究结果表明:TB12钛合金经过780~850℃×0.5 h的热处理即可实现完全固溶处理。在固溶状态TB12钛合金具有近60GPa的较低弹性模量、1 000 MPa的较高抗拉强度、优良的抗剪强度和良好的塑性,满足生物医用钛合金所需要的高强度和低模量的匹配。在固溶时效状态,TB12钛合金具有高达1 300 MPa的高强度和大于5%的延伸率。 相似文献
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Nacer Zazi Madjid Ifires Sofiane Mehala Jean Paul Chopart 《Russian Journal of Non-Ferrous Metals》2017,58(5):516-524
In this work, we have studied the effects of solution heat treatment followed by ageing on the corrosion behavior of AA2014 aluminum alloy welded by AA5554 aluminum alloy. Two samples are then analyzed, in the first case the solution heat treatment is followed by quenching and natural ageing of 90 days (sample 1), and in the second one, the solution heat treatment is followed by quenching and artificial ageing of twelve hours at 190°C (sample 2). The principal observations can be summarized as: evaporation of magnesium in fusion zone, and diffusion of magnesium and copper from the heat affected zone to the fusion zone were identified. Solution heat treatment, quenching and 90 days of natural ageing leads to a uniform corrosion in the heat affected zone and in the fusion one, when the material is immersed for ten seconds in Keller reagent solution. After immersion in 0.3% NaCl chloride solution, and after solution treatment and quenching, we observed that applied artificial ageing at 190°C causes localized corrosion surrounding precipitates and then develops uniform corrosion in all zones, particularly in the fusion one. Finally, it is noted that the surface of different zones became nobler after applying solution heat treatment followed by natural ageing. 相似文献
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Effects of heat treatments on microstructure and mechanical properties of Mg-15Gd-5Y-0.5Zr alloy 总被引:1,自引:0,他引:1
Microstructure and mechanical properties of Mg-15wt.%Gd-5 wt.%Y-0.5wt.% Zr alloy were investigated in a series of conditions. The eutectic was dissolved into the matrix and there was no evident grain growth after solntionized at 525 ℃ for 12 h. The evolution of the phase constituents from as-cast to cast-T4 was as follows: α-Mg solid solution+Mg5(Gd,Y) entectic compound→α-Mg solid solution+ spheroidized Mg5(Gd, Y) phase→α-Mg supersaturated solid solution+cuboid-shaped compound (Mg2Y3Gd2). And the precipitation sequences of Mg-15Gd-5Y-0.5Zr alloy were observed, according to the hardness response to isothermal ageing at 225-300 ℃ for 0-128 h. 相似文献
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Effect of silicide precipitation on tensile properties and fracture of alloy Ti-6Al-5Zr-0.5Mo-0.25Si
The effect of silicon in solid solution and in the form of suicides has been studied on the tensile properties and fracture
behavior of alloy Ti-6Al-5Zr-0.5Mo-0.25Si (alloy 685). The heat treatment to hold silicon in solid solution consists of solutionizing
at 1323 K for 0.5 hour under vacuum (∼10-5 MPa), followed by water quenching, and the treatment to precipitate suicides involves subsequent aging of the solutionized
and water quenched specimens at 1073 K for 24 hours. There is only marginal effect of the aging treatment on strength values;
however, the ductility parameters are found to be drastically reduced. There are marked differences in the fracture behavior
of the alloy in the as-quenched and the quenched and aged conditions. While the fracture surface of the unaged specimen shows
characteristic dimples, there is a large number of facets on the fracture surface of the aged specimen. The facets in the
central region are relatively smaller in size than those in the peripheral zone. The central facets show fluted features at
higher magnifications; however, the peripheral facets are usually featureless. The faceted fracture in the aged condition
is attributed to enhanced tendency for heterogeneous planar slip. The fracture characteristics correlate with the observed
differences in the ductility in the two conditions. 相似文献
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J. Menghani S. K. Agrawal Vikram Agarwal Dhaval Bhatt 《Transactions of the Indian Institute of Metals》2012,65(1):107-109
Reduced weight of automobiles for the purpose of fuel economy has encouraged the use of light metals especially aluminium
alloys. A356 Al alloy containing 7% Si and 0.3% Mg is widely used in automobile and aircraft industries due to excellent castability,
good corrosion resistance and good pressure tightness. A356 is age hardenable alloy and there is appreciable improvement in
strength and hardness achievable due to precipitation of intermetallic compound Mg2Si. In the present investigation, aluminium alloy A356 with and without rare earth (RE) addition (0.5 wt%) was subjected to
single ageing as well as double aging treatment. The results were compared for mechanical properties like hardness and ultimate
tensile strength with the material not containing RE additions. 相似文献