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在Gleebe-1500热模拟机上对0H4049合金进行了热模拟压缩实验,采用动态材料模型建立了合金的热加工图.基于热加工图研究了GH4049合金在温度为1060~1180℃、应变速率为0.1~50s-1条件下的热变形特性.结果表明,GH4049合金的热变形失稳区域集中在温度为1060~1110℃、应变速率为0.7~50s-1及温度为1120~1180℃、应变速率为1.8~50s-1的两个区域内;在合金的热变形稳定区域内,温度为1110~1175℃、应变速率为0.1~1.8s-1是合金典型的动态再结晶区域,对应的峰值效率为32%. 相似文献
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通过热模拟压缩实验研究了GH2907合金在变形温度为950~1100℃、应变速率为0.01~10s-1、变形量为60%条件下的热变形行为,流变应力随着变形温度的升高或应变速率的降低而显著降低;根据Arrhenius方程和Zener-Hollomon参数,计算了热变形激活能Q,建立了GH2907合金的热变形本构方程;根据动态材料模型,确定了GH2907合金在不同应变下的功率耗散图,功率耗散效率η较高的区域位于温度为1050~1100℃,应变速率为0.01~0.03s-1范围,在该变形区域内组织发生了明显的动态再结晶现象;基于Preased失稳判据,绘制了GH2907合金在不同应变下的热加工图,流变失稳区位于高温高应变速率区域,即温度为970~1100℃,应变速率为0.6~10s-1范围,在该变形区域内动态再结晶晶粒沿着绝热剪切带和局部流动分布。根据GH2907合金热加工图及微观组织分析得到适宜的加工区域是温度为1050~1100℃,应变速率为0.01~0.03s-1范围。 相似文献
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三维热加工图描述了功率耗散区和流动失稳区随着应变速率、温度和应变的变化。采用Gleeble-1500D热/力模拟试验机在变形温度950~1200℃,应变速率0.05~5 s~(-1)的条件下对X12合金的热变形行为进行了研究。考虑应变对X12合金可成形性的影响,基于动态材料模型,建立了X12合金的三维热加工图,确定了X12合金热变形的最佳参数为应变大于0.3,温度为1150~1200℃,应变速率为0.05~0.63 s~(-1)。通过对有限元软件DEFORM的二次开发,将X12合金的三维加工图数据与DEFORM进行集成,对?8 mm×12 mmX12合金圆柱试样在不同温度及应变速率下的压缩过程进行了有限元模拟,得到了该试样压缩过程中的功率耗散系数及流动失稳系数分布图,验证了X12合金的最佳热变形工艺参数。 相似文献
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用热加工图研究铸态和挤压态ZE41A镁合金的热加工性能 总被引:1,自引:0,他引:1
采用热加工图研究铸态和挤压态ZE41A镁合金的热变形行为和组织演变。在温度250-450℃,应变速率0.001-1.0s-1的条件下,对铸态和挤压态合金进行抗压测试,建立热加工图。通过显微组织观察确定动态再结晶和不稳定区域。挤压态ZE41A镁合金比铸态合金具有较高的流变应力,较高的能量损耗率和较小的不稳定区域。由于晶粒的细化、材料孔隙度的降低、硬化和强化,挤压态镁合金具有良好的热加工性能。 相似文献
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采用Gleeble-1500热模拟机对GH738镍基高温合金进行高温热压缩变形实验,分析该合金在变形温度1000~1160℃、应变速率0.01~10s-1、工程变形量15%~70%条件下流变应力的变化规律。确定GH738合金热变形方程,建立热加工图(Processing map),并通过组织观察对热加工图进行解释。GH738合金热变形激活能Q为499kJ/mol;热加工图随不同变形量而变化,在应变速率较低,温度较高的状态下,能量耗散效率较高。综合应变量为0.2,0.4,0.6和0.8应变量下的热加工图,确立了该合金最佳热加工"安全通道",为GH738高温合金热加工工艺优化提供理论依据。 相似文献
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通过对Thermecmaster-Z型热加工模拟试验机上等恒等应变速率压缩试验结果表明,首次提出了钴基高温合金MP159的热加工工艺参数范围。 相似文献
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采用Gleeble-3800型热模拟试验机研究了变形参数对Haynes 282合金热变形时流动应力的影响规律,建立了Haynes 282合金高温塑性变形时的热加工图。结果表明:在达到峰值应变后,当变形温度在1000℃及以下时,合金的软化速率一直大于硬化速率,应力持续下降;当变形温度大于1000℃时,加工硬化速率和再结晶软化速率达到动态平衡。合金热加工图包含两个危险区,危险区I:温度900~1000℃、应变速率0.1~10 s-1和危险区Ⅱ:温度1000~1200℃、应变速率1~10 s-1;热加工图中失稳区是由温度900~1000℃、应变速率0.1~10 s-1和温度1000~1150℃、应变速率0.1~1 s-1组成的区域;安全区对应的温度范围为1000~1200℃,应变速率为0.01~0.1 s-1,该区的功率耗散系数为0.34~0.44,是合适的热加工区。 相似文献
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利用热加工图分析了FGH4096粉末高温合金的热变形行为,评定了益加工区,预测了变形失稳区;结合热加工图与组织分析建立了此合金在真应变0.65下的微观变形机制示意图。不同应变量下获得的热加工图表现出一致的特征:从低温/低速区到高温/高速区存在明显的益加工带;而低温/高速区和高温/低速区则是被预测的变形失稳区。HIPedFGH4096合金的热加工性能直接受动态再结晶的影响:在低温/低速和高温/高速下发生的完全再结晶及其粗化过程均对应着高的能量耗散率,有利于合金的热加工;而在低温/高速下动态再结晶受到抑制,潜在着原始颗粒边界萌生裂纹而导致变形失稳的可能性。 相似文献
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Isothermal compression of TC11 alloy at the deformation temperatures ranging from 1023 to 1323 K with an interval of 20 K, the strain rates of 0.001, 0.1, 1.0, and 10.0 s<'-1>, and the height reductions of 50% and 70% was conducted on a Gleeble- 1500D thermomechanical simulator. According to the experimental results, the isothermal compression and the processing maps of TC11 alloy at different strains were drawn by using the dynamic material model (DMM). Based on the processing maps, the proper forging parameters, including a combination of defor- mation temperature and strain rate, vary with the strain in different phases of TC11 alloy. 相似文献
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Isothermal compression of TC11 alloy at the deformation temperatures ranging from 1023 to 1323 K with an interval of 20 K, the strain rates of 0.001, 0.1, 1.0, and 10.0 s-1, and the height reductions of 50% and 70% was conducted on a Gleeble-1500D thermomechanical simulator. According to the experimental results, the isothermal compression and the processing maps of TC11 alloy at different strains were drawn by using the dynamic material model (DMM). Based on the processing maps, the proper forging parameters, including a combination of defor-mation temperature and strain rate, vary with the strain in different phases of TC11 alloy. 相似文献
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本文研究了不同形变热处理工艺参数对冷轧态镍基高温合金中晶界特征分布演变的影响。结果表明,在退火处理过程中,生长事故模型是静态再结晶(SRX)晶粒中新Σ3晶界形成的主要机制。随着退火时间和退火温度的增加,晶界迁移时间延长,晶界迁移速度加快,从而增加了生长事故的发生频率,促进了Σ3晶界的形成。此外,随着应变的增加,Σ3晶界的比例先减小后增大。在冷轧变形量为0.1和0.7时,Σ3晶界的比例均可达到60%左右,这与大晶粒团簇的形成密切相关。此外,本文还详细分析了不同工艺参数下,Σ1晶界、共格Σ3晶界、非共格Σ3晶界、Σ9晶界、Σ27晶界和随机晶界的演变规律。 相似文献
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G. S. Avadhani 《Journal of Materials Engineering and Performance》2003,12(6):609-622
Maraging steels possess ultrahigh strength combined with ductility and toughness and could be easily fabricated and heat-treated.
Bulk metalworking of maraging steels is an important step in the component manufacture. To optimize the hot-working parameters
(temperature and strain rate) for the ring rolling process of maraging steel used for the manufacture of rocket casings, a
systematic study was conducted to characterize the hot working behavior by developing processing maps for γ-iron and an indigenous
250 grade maraging steel. The hot deformation behavior of binary alloys of iron with Ni, Co, and Mo, which are major constituents
of maraging steel, is also studied. Results from the investigation suggest that all the materials tested exhibit a domain
of dynamic recrystallization (DRX). From the instability maps, it was revealed that strain rates above 10 s−1 are not suitable for hot working of these materials. An important result from the stress-strain behavior is that while Co
strengthens γ-iron, Ni and Mo cause flow softening. Temperatures around 1125 °C and strain rate range between 0.001 and 0.1
s−1 are suitable for the hot working of maraging steel in the DRX domain. Also, higher strain rates may be used in the meta-dynamic
recrystallization domain above 1075 °C for high strain rate applications such as ring rolling. The microstructural mechanisms
identified from the processing maps along with grain size analyses and hot ductility measurements could be used to design
hot-working schedules for maraging steel. 相似文献
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Effect of extrusion processing parameters on microstructure and mechanical properties of as-extruded AZ31 sheets 总被引:1,自引:1,他引:0
The AZ31 sheets were prepared by extrusion.The effects of the extrusion processing parameters including the temperature extrusion ratio,and structure of the extrusion die on the microstructure and mechanical properties of the as-extruded AZ31 sheets were investigated.The results show that the partial grains grow abnormally.and the mechanical and anisotropic properties of the as-extruded AZ31 sheets have little change at the extrusion temperatures of 380-400℃and the extrusion ratio of 13.3.With the increa... 相似文献
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研究热挤压以及热处理对镍基高温合金FGH96原始颗粒边界(PPB)、γ′相、MC型碳化物及γ基体的影响。结果表明:PPB是由大的γ′相、MC型碳化物和少量的氧化物构成。可通过热挤压将γ′相尺寸由微米级细化到纳米级,并达到消除PPB的效果。热挤压态FGH96合金的晶粒长大激活能为402.6 kJ/mol,表明在低于γ′相完全溶解的温度时,晶粒长大受到γ′相的抑制。在稍高于γ′相完全溶解的温度时,MC型碳化物起到钉扎晶界的作用并阻碍晶粒异常长大。 相似文献
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