共查询到19条相似文献,搜索用时 140 毫秒
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针对高强度镁合金管材挤压过程中坯料成形问题,设计了四套具有不同焊合室高度的管材挤压模具,对AZ91镁合金管材分流模挤压工艺过程进行了有限元分析和挤压试验。结果表明,变形程度指标等效应变标准方差由高到低顺序为:H=9mm>H=12mm>H=18mm>H=15mm,其中焊合室高度为15mm时变形最均匀;AZ91镁合金经分流模挤压,粗大的树枝晶及网状第二相β-Mg_(17)Al_(12)被击碎重溶,并且发生再结晶,组织和性能得到明显改善。 相似文献
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往复挤压及正挤压AZ91D镁合金丝材的组织及性能 总被引:2,自引:0,他引:2
将AZ91D镁合金铸锭在330℃往复挤压4道次后,在300℃连续正挤压制成Ф5mm的丝材,用OM,SEM分析不同方式挤压前后组织的变化,研究往复挤压及随后正挤压对其组织与性能的影响。研究表明,AZ91D镁合金往复挤压4道次及连续正挤压制备的矽5mm丝材组织均为等轴晶,晶粒尺寸分别为小于10um及1um~3um。经往复挤压及随后的正挤压,AZ91D铸造镁合金的综合力学性能均可得到显著提高,其主要原因是基体组织α-Mg和强化相β-Mg17Al12的细化。往复挤压4道次后,材料真应变高达20.36,正挤压过程中等效应变速率达到0.192s^-1,AZ91D镁合金往复挤压及正挤压晶粒的细化机制主要包括破碎、动态再结晶和动态回复。 相似文献
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《材料热处理学报》2016,(2)
研究了具有不同析出相含量的AZ91D挤压镁合金在拉伸变形中出现的Portevin-Le Chatelier(PLC)现象,讨论了析出相对其产生PLC效应的影响规律,指出AZ91D挤压镁合金产生PLC效应的微观机理。结果表明:Al溶质原子的浓度是影响AZ91D挤压镁合金产生PLC效应的主要因素,β-Mg_(17)Al_(12)相的析出抑制了AZ91D挤压镁合金不稳定塑性行为。当β-Mg_(17)Al_(12)相析出量较高时,AZ91D挤压镁合金表现为稳定的塑性流变过程,其对应的应力-应变曲线为光滑的曲线;随着β-Mg_(17)Al_(12)相析出量的降低,固溶于Mg基体中的Al原子量增加,固溶体内溶质原子浓度提高,拉伸曲线表现出明显的锯齿屈服并逐渐剧烈,即AZ91D挤压镁合金的PLC效应随β-Mg_(17)Al_(12)相析出量的减少和Al溶质原子浓度的提高而增强;当β-Mg_(17)Al_(12)相含量为1.0mass%,对应的曲线上只出现一个锯齿抖动,这是AZ91D挤压镁合金产生PLC效应的临界状态。 相似文献
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《特种铸造及有色合金》2016,(6)
采用铸锻复合一体化成形技术制备了AZ91D镁合金,研究了锻压变形量对AZ91D镁合金组织与力学性能的影响。结果表明,锻压变形量越大,锻压对模具型腔内凝固过程的AZ91D镁合金的强制补缩效果越好,收缩裂纹和缩孔越少,AZ91D镁合金的抗拉强度和伸长率越高。当锻压变形量为2mm时,锻压变形能够完全消除收缩裂纹和缩孔,压实显微组织。当锻压变形量为5mm时,AZ91D镁合金的抗拉强度和伸长率分别为240.3 MPa和4.14%,与未锻压相比,此时AZ91D镁合金的抗拉强度和伸长率分别提高了34.7%和52.7%。 相似文献
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B.Y. Yu C.L. Bao H.W. Song Z. Liu H.P. Yu 《金属学报(英文版)》2006,19(3):203-208
The effect of extrusion ratio on microstruetures and mechanical properties of magnesium alloy AZ91D extruded tube at 430℃ has been studied. After the evolution of microstracture and mechanical properties of AZ91D during extrusion were studied, the following parameters were obtained: tensile strength reached the climax value of 306.9MPa and elongation peak value of 10.1% at an extrusion ratio of 7.125, and with the increase of the extrusion ratio to 7.45, yield strength reached a top value of 285.795MPa with decreased tensile strength and elongation. It was concluded that mechanical properties of magnesium alloys AZ91D could be enhanced by adjusting the extrusion ratio near recrystallization. 相似文献
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Surendra Kumar 《Journal of Materials Engineering and Performance》2006,15(1):41-46
Rapidly solidified magnesium alloys show great potential for application in automotive and aerospace industries. In this study,
Mg-Al-Zn alloys (AZ91) were rapidly solidified by a melt-spinning process to form ribbons. Pulverized ribbons were cold-compacted
and then hot-extruded to form rods. During extrusion, a specially designed die with constant strain rate profile was used
and found to be advantageous. By properly establishing the complete process, extruded rods of rapidly solidified AZ91 alloys
exhibiting good combination of room temperature strength and ductility were produced. Microstructural investigations were
carried out on melt-spun ribbons and extruded rods. Effects of extrusion die shape, extrusion ratio, and extrusion temperature
on mechanical properties of the extruded rods were also investigated. 相似文献
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挤压比为4:1,将铸态AZ91镁合金分别在250,300和350℃下进行挤压,随后进行析出硬化处理(T6)。经过热挤压和析出硬化处理后,铸态AZ91镁合金中粗大的和偏析Mg17Al12析出相被细化并均匀分布在α-镁基体中。在不同的挤压温度下合金中发生了部分或全部动态再结晶。经挤压后,该合金的极限抗拉强度从铸态的190MPa增加到570MPa。AZ91镁合金的时效硬化特征与晶粒尺寸有关。在250、300和350℃下以4:1的挤压比挤压该合金后,获得峰值硬度的时效时间分别为35、30和20h。SEM观察到在AZ91基体中存在均匀细小的Mg17Al12析出相。 相似文献
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挤压变形制备高强度镁合金的探索 总被引:1,自引:0,他引:1
调整AZ91镁合金中Al和Zn元素的成分,采用传统的熔炼工艺制成镁合金铸锭,再经过挤压变形制成试样。通过对试样的分析研究,探讨挤压加工对镁合金组织和力学性能的影响规律,以期试制出性能优越的高强度镁合金。 相似文献
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AZ31 magnesium alloys were hot-extruded at 573 K and 623 K with extrusion ratio(λ) of 20,35 and 50.The corrosion and mechanical behavior of hot-extruded AZ31 were studied by galvanic tests and tensile tests.The microstructures of the studied AZ31 alloys were also investigated with optical microscope.The results show that,compared with the as-cast AZ31 alloy,the corrosion potentials of all hot-extruded AZ31 alloys are increased by 60 mV.Moreover,at the extrusion temperature of 623 K,the galvanic current o... 相似文献
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Particulate reinforced magnesium matrix nanocomposite prepared with semisolid stirring assisted ultrasonic vibration was subjected to extrusion at 350 °C with an extrusion ratio of 12:1. Extrusion of the SiCp/AZ91 nanocomposite induced large scale dynamic recrystallization resulting in a fine matrix microstructure. There were two kinds of zones in the extruded nanocomposite: SiC nanoparticle bands parallel to the extrusion direction and refined-grain zones between the SiC nanoparticle bands. In the SiC nanoparticle bands, there were SiC nanoparticles along the boundaries of refined grains. The distribution of SiC nanoparticles was uniform although some agglomerates of SiC nanoparticles still existed in the SiC nanoparticle bands. The ultimate tensile strength, yield strength and elongation to fracture of the SiCp/AZ91 nanocomposite were simultaneously improved by extrusion. Results from the extruded SiCp/AZ91 nanocomposite tensile testing at different temperatures (75, 125, 175 and 225 °C) revealed an increase of the tensile strength and ductility values compared with the unreinforced and extruded AZ91 alloy. 相似文献
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Al-Ti、Al-Ti-C中间合金对AZ91D镁合金组织和性能的影响 总被引:1,自引:0,他引:1
研究了Al-5Ti、Al-5Ti-0.25C和Al-8Ti-2C中间合金对AZ91D镁合金的组织、力学性能和耐腐蚀性能的影响。结果表明,添加Al-5Ti中间合金使晶粒粗化,而添加Al-5Ti-0.25C和Al-8Ti-2C中间合金使晶粒细化,Al-8Ti-2C中间舍金的细化效果明显且细化后组织细小均匀;添加Al-5Ti中间合金使合金的力学性能降低,而添加Al-5Ti-0.25C和Al-8Ti-2C中间合金均使合金的拉伸强度和伸长率得到了提高;添加Al-5Ti、Al-5Ti-0.25C和Al-8Ti-2C中间合金均使合金的耐腐蚀性能得到了改善。对于AZ91D合金而言,Al-8Ti-2C中间合金是一种良好的晶粒细化剂。 相似文献