在线挤压淬火对地铁列车用6005A合金力学性能及微观组织的影响

为地铁列车车体用600A铝合金进行了在线挤压淬火正交实验和透射电镜分析，研究了挤压温度、挤压速度、淬火方式对合金力学性能的影响。结果表明：淬火方式对合金性能的影响最大，水淬可使合金获得高的力学性能；提高挤压温度和挤压速度也可在一定程度上提高合金力学性能。透射电镜分析表明，在线挤压淬火工艺对合金力学性能的影响实质上与β强化相的数量、大小、分布密切相关。     

地铁列车用7005铝合金力学性能及微观结构分析

对地铁列车车体用7005铝合金进行了在线挤压淬火实验和微观组织分析,研究了挤压温度,挤压速度,淬火方式以及时效条件对合金力学性能的影响,实验结果表明：降低挤压速度和淬火速度可在一定程度上提高合金力学性能,但对力学性能影响最大的两个因素是挤压温度和时效时间,透射电镜分析表明,较低的挤压温度,适当短一些的时效时间,可使合金中的强化η'相颗粒细小,分布均匀,且晶界附近无沉淀带窄,因而易使合金获得高的力学性能,过高的挤压温度和过长的时效时间均易使合金产生过时效,析出相颗粒粗大,无沉淀带宽,导致合金力学性能恶化。     

基于ALE方法大挤压比Al-Cu-Mg合金等温挤压研究

为了获得大挤压比Al-Cu-Mg合金高精度等温挤压件,有必要精确控制其均匀的挤压出口温度和变形组织。为此,基于任意拉格朗日-欧拉（ALE）方法,采用ABAQUS有限元软件对其等温挤压过程进行模拟。通过热压缩试验获得了Al-Cu-Mg合金在不同温度和应变速率下的真应力-真应变本构关系,建立了一个新的等温挤压过程多场耦合计算模型。通过该模型,研究了挤压速度、坯料温度、模具温度对出口温度的影响规律以及挤压产品温度场、应变速率场的分布特点;并通过开展Al-Cu-Mg合金铸棒等温挤压工艺实验验证了所模拟等温挤压工艺参数的准确性,并对变形材料进行了EBSD分析和力学性能测试。结果表明：0.5mm/s挤压速度可保持模孔温度基本恒定,其中坯料温度450℃,挤压筒430℃,以及模具温度为400℃,挤压后试样的晶粒明显细化,择优排列形成平行于挤压方向的＜111＞丝织构,表现出优异的拉伸性能。     

基于RBF神经网络的6005A铝合金挤压在线淬火力学性能预测

为了研究6005A铝合金在线挤压淬火工艺参数对材料力学性能的影响,采用径向基(RBF)神经网络,以挤压速度和挤压温度为输入变量,以材料的断后伸长率、屈服强度、抗拉强度为输出变量,建立了6005A铝合金挤压在线淬火T5时效后的力学性能预测模型,绘制了挤压速度、挤压温度对力学性能影响的三维网格模型和等高线图,能较为直观地反映它们之间的影响规律,并通过实验证明了预测模型的预测精度满足生产需要,可以为6005A铝合金材料的实际生产提供技术支持。     

淬火介质温度对汽车缸盖挤压件微观组织和力学性能的影响

为了改善汽车缸盖脱模挤压后的组织与性能,采用不同的淬火介质温度对缸盖挤压件进行热处理,并分析淬火介质温度对缸盖挤压件稀土镁合金的显微组织、物相组成及力学性能的影响。结果表明,随淬火介质温度从20℃升高至80℃,合金的晶粒先细化后粗化,其力学性能也随之先提高后下降;但合金的物相组成未发生明显变化。     

热加工工艺对Al-Mg-Si系合金型材性能的影响

Al-Mg-Si(6×××)系合金是最重要的挤压铝合金,其中又以6063、6082、6060和60054种合金及其变种应用最广泛。全面而深入地分析了锭坯的均匀化及冷却方式,锭坯加热温度与加热方式,挤压成型工艺,淬火方式,人工时效及停放时间等对上述4种合金的可挤压性、挤压力、最大生产能力及力学性能等的影响。     

Fe—P—C粉末合金临界区热处理的研究

本文研究了Ｆｅ－Ｐ－Ｃ三元系粉末合金经不同温度淬火及不同温度回火后的组织和性能。试验结果表明：临界区热处理与常规温度处理相比。硬度略有升高，冲击韧性有较大增加，本文并对强韧化机理进行了探讨。     

2219铝合金Φ42mm×15mm管材的生产工艺研究

2219铝合金Φ42 mm×15 mm(外径×壁厚)管材经淬火、人工时效后(T6状态),用户要求它有较高的强度和较好的车削性能。从2219铝合金管材的挤压温度、淬火和时效工艺制度进行试验研究,对不同工艺制度生产的管材进行力学性能检测,最终确定了最佳的挤压、淬火、人工时效工艺制度,使该合金管材的力学性能满足了用户的要求。     

6101B铝合金导电轨挤压及热处理工艺研究

本文通过研究不同挤压速度、淬火方式及时效制度,分析了6101B铝合金导电轨直流电阻及力学性能不合格的原因,并制定相应挤压热处理制度,以满足客户要求。     

淬火对Fe—Mn—Si—Cr—Ni记忆合金回复率的影响

研究淬火加热温度对（Ｗ％）Ｆｅ－１４．９Ｍｎ－６．３Ｓｉ－８．８Ｃｒ－５．２Ｎｉ形状记忆合金形状回复率的影响。试验结果表明，形状回复率随淬火加热温度升高而提高，７００℃￣８００℃淬火，达到最大值，随后回复率随淬火加热温度进一步升高而降低。淬火加热温度越高，热诱发ε马氏体数量越多。热诱发ε马氏体对形状记忆效应具有双重作用。适量的热诱发ε马氏体有利于提高形状回复率。     

Effects of fluidised bed quenching on heat treating characteristics of cast Al–Si–Mg and Al–Si–Mg–Cu alloys

Abstract

The quench sensitivity of Al–Si–Mg (D357 unmodified and Sr modified), and Al–Si–Mg–-Cu (354 and 319 Sr modified) cast alloys was investigated using a fluidised bed (FB). The average cooling rate of castings in the fluidised bed is lower than those quenched in water; the cooling rate first increases to a certain maximum and then decreases during quenching. The change in the cooling rate during quenching in water was more drastic, where the cooling rate varied from 0 to ?80 K s^?1 in less than 8 s, as compared with those quenched in FB, where the cooling rate varied from 0 to ?14 K s^?1 in 18 s. The FB quenching resulted in the formation of several metastable phases in Al–Si–Mg–Cu alloys; in contrast, no such transformation was observed during water quenching. The T4 yield strength of the FB quenched alloys was greater than water quenched alloys owing to the formation of a greater volume fraction of metastable phases in the FB quenched alloys. The tensile properties of T6 treated alloys show that Al–Si–Mg alloys (both unmodified and Sr modified) are more quench sensitive than Al–Si–Mg–Cu alloys. The high quench sensitivity of the Al–Si–Mg alloys is because GP zones are not formed, whereas GP zones are formed during quenching of the Al–Si–Mg–Cu alloys as predicted by time temperature transformation and continuous cooling transformation) diagrams.     

6063铝合金连续挤压工艺研究

试验表明,控制连续挤压产品机械性能的关键因素是挤压温度与６０６３铝合金中的Ｍｇ含量。     

等通道转角挤压工艺参数对铝镁合金组织和性能的影响

等通道转角挤压技术(ECAP)是一种新型获得超细晶粒的重要制备方法之一,同时也是提高材料力学性能的根本途径之一。影响ECAP对铝、镁合金晶粒细化的因素有多方面,综述了ECAP各工艺参数对铝镁合金组织和性能的影响,其主要工艺参数包括模具结构、挤压道次、挤压温度、挤压速度以及挤压路径。     

Enhancing room temperature mechanical properties of Mg–9Al–Zn alloy by multi-pass equal channel angular extrusion

Influence of equal channel angular extrusion on room temperature mechanical properties of cast Mg–9Al–Zn alloy was investigated. The results show that room temperature mechanical properties of Mg–9Al–Zn alloy, such as yield strength, ultimate tensile strength and elongation, can be improved heavily by equal channel angular extrusion. Processing routes, processing temperature and extrusion passes have important influence on room temperature mechanical properties of processed Mg–9Al–Zn alloy by equal channel angular extrusion. The optimum room temperature mechanical properties such as yield strength of 209 MPa, ultimate tensile strength of 339 MPa and elongation of 14.1%, can be obtained when Mg–9Al–Zn alloy was processed by equal channel angular extrusion for 6 passes at route B_C at 498 K. Large bulk materials of Mg–9Al–Zn alloy with average grain size of 4 μm and high mechanical properties can be prepared.     

在线淬火工艺对6005A合金挤压型材组织与性能的影响

采用正交试验和模拟试验的方法, 研究了在线淬火方式、淬火冷却速度及淬火延迟时间对6005A铝合金空心型材组织和性能的影响. 结果表明 提高在线淬火冷却强度比提高挤压温度和挤压速度对改善型材性能的效果更明显, 型材强度随淬火冷却速度的增大明显提高, 而延伸率并无明显降低; 在线精密水雾淬火可使型材性能满足车辆型材使用要求; 缩短在线淬火前型材在室温环境下的停留时间, 可以显著提高型材强度性能.     

Effects of extrusion and heat treatments on microstructure and mechanical properties of Mg–8Zn–1Al–0.5Cu–0.5Mn alloy

The effects of extrusion and heat treatments on the microstructure and mechanical properties of Mg–8Zn–1Al–0.5Cu– 0.5Mn magnesium alloy were investigated. Bimodal microstructure is formed in this alloy when it is extruded at 230 and 260 °C, and complete DRX occurs at the extruding temperature of 290 °C. The basal texture of as-extruded alloys is reduced gradually with increasing extrusion temperature due to the larger volume fraction of recrystallized structure at higher temperatures. For the alloy extruded at 290 °C, four different heat treatments routes were investigated. After solution + aging treatments, the grains sizes become larger. Finer and far more densely dispersed precipitates are found in the alloy with solution + double-aging treatments compared with alloy with solution + single-aging treatment. Tensile properties are enhanced remarkably by solution + double-aging treatment with the yield strength, tensile strength and elongation being 298 MPa, 348 MPa and 18%, respectively. This is attributed to the combined effects of fine dynamically recrystallized grains and the uniformly distributed finer precipitates.     

Microstructure and properties of friction stir welded aluminium alloys

Aluminium alloy 7136 belongs to the Al–Zn–Mg–Cu group of aluminium alloys strengthened by precipitation. These alloys offer very good properties, i.e. high strength combined with good corrosion resistance, which makes them suitable for aerospace applications. The limited range of applications of these alloys is due to problems associated with their welding. The Al–Zn–Mg–Cu alloys are classified as non-weldable. The aim of this study was to determine the quality and properties of friction stir welded (FSW) joints of alloy 7136-T76. This article presents the results of a detailed study into the microstructure and mechanical properties of FSW welds. The paper demonstrates that the FSW method is suitable for joining Al–Zn–Mg–Cu alloys. The FSW joints are of good quality and high mechanical properties. Tests of joints created at various tool rotation speeds have shown that joints of suitable quality, in terms of microstructure and properties, can be obtained for a relatively wide range of process parameters. The tool rotation speeds applied during the welding process did not have a significant influence on the quality of the welds.     

Validation of a systematic approach to modeling spray quenching of aluminum alloy extrusions, composites, and continuous castings

Optimal cooling of aluminum alloys following the high- temperature extrusion process suppresses precipitation of intermetallic compounds and results in a part capable of possessing maximum strength and hardness after the subsequent age- hardening process. Rapid quenching suppresses precipitation but can lead to large spatial temperature gradients in complex- shaped parts, causing distortion, cracking, high residual stress, and/or nonuniform mechanical properties. Conversely, slow cooling significantly reduces or eliminates these undesirable conditions but allows considerable precipitation, resulting in low strength, soft spots, and/or low corrosion resistance. This study presents a systematic method of locating and operating multiple spray nozzles for any shaped extrusion such that uniform, rapid cooling and superior mechanical and metallurgical properties are achieved. A spray nozzle data base was compiled by measuring the distribution of spray hydrodynamic parameters (volumetric spray flux, mean drop diameter, and mean drop velocity) throughout the spray field of various industrial nozzles. Spray heat transfer correlations, which link the local spray hydrodynamic parameters to the heat transfer rate in each of the boiling regimes experienced by the surface, defined the spatially nonuniform boundary conditions in a numerical model of the quenching process that also accounted for interference between adjacent spray fields. New correlations, offering increased accuracy and less computational time, were formulated for the high- temperature boiling regimes which have a critical influence on final mechanical properties. The quench factor technique related predicted thermal history to metallurgical transformations occurring within the extrusion to predict hardness distribution. The validity of this unique approach was demonstrated by comparing model predictions to the temperature response (and hardness after artificial aging) of an L- shaped Al 2024- T6 extrusion to quenches with multiple, overlapping water sprays. The validation study reported herein concludes by exploring the possibility of applying quenching technology to improving the properties of extruded metal- matrix composites such as SiC_p/Al 6061 and cast alloys.     

6005A合金的加工特性和性能

６００５Ａ合金是一种中等强度铝合金，主要用作车辆的薄壁、空心壁板和一些结构型材，介绍了６００５Ａ合金的化学成分和性能，叙述了不同的铸锭均匀化制度和其应用范围，通过与６０６３和６０６１合金的挤压速度和淬火敏感性等作比较，说明６００５Ａ合金具有优良的挤压性能，能在挤压机列上实现淬火。