共查询到20条相似文献,搜索用时 187 毫秒
1.
利用压缩实验数据建立了Zr55Cu30Ni5Al10大块非晶合金在过冷温度区域内的流动应力模型,并选用DE-FORM-3D软件对杯形非晶合金零件超塑性微挤压成形过程进行了模拟,得到了挤压过程中坯料的速度场、应变速率场和应力场的分布规律。分析发现在挤压过程中材料的应变速率极不均匀,因此,对材料的流动变形过程进行了合理分区,分析各区域的形状、大小及变化历程。在此基础上,利用反挤压工艺成功挤出了外径为2.2 mm、壁厚为0.05 mm的杯形零件。SEM显示,该成形件壁厚均匀,尺寸和几何形状满足设计要求。 相似文献
2.
3.
4.
5.
Zr55Al10Ni5Cu30大块非晶合金的超塑性挤压成形性能 总被引:8,自引:3,他引:8
通过示差扫描量热分析确定了Zr55Al10Ni5Cu30大块非晶合金的过冷温度区域范围,采用应变速率突变压缩实验分析了合金在450℃时的力学性能,研究了合金在不同挤压速度、不同真空度等工艺条件下的挤压成形性能.结果表明:Zr55Al10Ni5Cu30大块非晶合金的玻璃化转变开始温度Tg为422.4℃,晶化开始温度Tx为482.4℃;在450℃、应变速率小于5×10-3s-1的条件下,合金的流动应力小于40 MPa在挤压速度为0.002~0.004mm/s范围内挤压时,合金的最大挤压载荷变化较小;在挤压温度为450℃时,合金的最大挤压力随着真空度(2~2×10-3Pa)的提高而增加;大块非晶合金在超塑性成形时呈现出比一般金属材料更大的摩擦阻力. 相似文献
6.
7.
8.
9.
10.
根据内花键轴零件的形状尺寸特点,分析内花键轴成形的工艺方式,运用有限元软件DEFORM-3D对内花键轴热挤压成形过程进行数值模拟,对成形过程中凸模的载荷-行程曲线和挤压件温度场进行分析,并研究坯料加预热温度和挤压速度对挤压力的影响,分析得到坯料的最佳加热温度范围为1100℃~1200℃,最合理的挤压速度为10mm/s左右,为同类零件的加工及生产提供理论依据。 相似文献
11.
热处理对Ti_(35)Zr_(30)Be_(27.5)Cu_(7.5)非晶合金压缩性能的影响 总被引:1,自引:1,他引:0
利用铜模铸造法获得了直径为2 mm的Ti35Zr30Be27.5Cu7.5块体非晶合金。采用X射线衍射(XRD)、扫描电镜(SEM)、差氏扫描量热仪(DSC)及压缩试验等方法研究了非晶合金的相结构、显微组织和热稳定性,以及热处理对其压缩强度及塑性的影响。结果表明:在553和583 K温度下分别保温5 h后,实验合金仍保持为非晶态;在613 K保温1 h后,有晶化相出现。Ti35Zr30Be27.5 Cu7.5非晶合金在583 K下保温1 h后其塑性变形量达到了6.57%,较热处理前提高了1倍,且保持了热处理前的强度,屈服强度和抗压强度分别为1921 MPa,2169 MPa。随着热处理温度的提高,非晶相含量减少,合金断裂强度、塑性变形量随之降低;同时合金断裂方式由韧性断裂转变为脆性断裂。 相似文献
12.
J.Wang* J.Chen Z.Zhao X.Y.Ruan National Die & Mold CAD Engineering Research Center Shanghai Jiaotong University Shanghai China 《金属学报(英文版)》2006,19(4):279-286
~~MODELING OF MICROSTRUCTURAL EVOLUTION IN MICROALLOYED STEEL DURING HOT FORGING PROCESS~~1 C.A. Hernandez, S.F. Medina and J. Ruiz, Acta Materialia 44 (1996) 155.
2 P.D. Hodgson and R.K. Gibbs, ISIJ International 32 (1992) 1329.
3 S.I. Kim, Y. Lee and S.M. Byon, Journal of Materials Processing Technology 140 (2003) 84.
4 A. Laasraoui and J.J. Jonas, Metall. Trans. 22A(1991) 1545.
5 S.F. Medina and J.E. Mancilla, ISIJ International … 相似文献
13.
针对二十辊轧机轧制过程中工作辊和轧件的复杂变化过程,基于有限元分析软件(Workbench)建立了工作辊和轧件的有限元模型;通过分析二十辊轧机轧辊间的几何位置关系,得到了工作辊压下量与支撑辊偏心角度之间的关系;采用结构动力学方程的瞬态算法对轧制过程进行了模拟计算,得到了轧辊、轧件的应力、应变情况以及轧制力曲线,并对轧制过程中工作辊和轧件的特性变化过程进行了分析。 相似文献
14.
15.
基于选区激光熔化技术(SLM),制备了BCC、FCC、FCCZ 3种不同拓扑单元的316L不锈钢多孔结构,验证了该技术成形复杂多孔结构件的可行性。对试样进行了准静态压缩试验,得到了多孔结构在压缩过程中的变形模式和力学响应曲线,对比分析了3种结构试样的力学性能。结果表明,FCCZ型多孔结构的抗压性能和能量吸收特性均优于BCC型和FCC型结构;利用ABAQUS/Explicit软件进行准静态压缩仿真,仿真结果和试验结果基本符合。 相似文献
16.
基于有限元分析的摩擦系数测定 总被引:2,自引:2,他引:0
在塑性体积成形有限元模拟中,摩擦模型和摩擦系数的确定是一个关键问题.本文采用圆环镦粗法研究体积成形中摩擦系数的确定.利用有限元分析确定一组摩擦系数标定曲线,用圆环镦粗试验确定圆环内径变化率百分比与圆环高度压缩百分比关系曲线.通过曲线对比得到模具材料和成形材料之间的摩擦系数.针对6A02CZ材料在钢模具中体积成形时6A02CZ材料与钢之间的摩擦系数进行确定,6A02CS材料在无润滑剂和润滑油做润滑剂两种情况下的摩擦系数分别为0.325和0.3.研究表明,采用有限元方法和圆环镦粗试验相结合的方法更适合塑性体积成形中的有限元分析. 相似文献
17.
1.IntroductionTherolledmaterial,mainlyashot,isverysensitivetometallurgicalandrolling--engineeringvariationswhichareofferedorconditionedbythetechnology.AInongthosevariations,alsotheinfluencesofthermomechanicalparametersonthedefonnationpropertiesoftherolledpiece,andontheProcessofsofteningcanbecoUnted,sincetheirfinaleffectistheformationofndcrostrtlctureoftheproductWhichisofteninhomogeneous.Inhomogeneousplasticdeformation,alwaysPresentinrealprocessesgischaracterizedbyaninhomogeneouscourseofstres… 相似文献
18.
The deformation behavior and macroscopic formability of a Zr-based bulk metallic glass composite (BMGC) has been investigated
in this study by performing a series of compression and laboratory-scale extrusion tests under various deformation rates within
the supercooled liquid temperature region. The morphology of Zr−Ti−Nb-rich dendrite precipitates after warm deformation was
first examined by using optical microscopy (OM) and a field emission scanning electron microscope (FE-SEM). The extrusion
of this BMGC alloy within the supercooled liquid temperature region was found more difficult than the extrusion of other Zr-based
monolithic BMG alloys, possibly due to the existence of dendrite phases hindering the characteristic viscous flow generated
in the amorphous phase. A FEM simulation has also been carried out by utilizing the stress-strain behaviors obtained from
high temperature compression tests, and the results have been compared with the experimental extrusion test results. The FEM
simulation results for the extrusion process as well as a processing map based on a dynamic materials model (DMM) were found
to agree relatively well with the actual macroscopic extrusion formability. 相似文献
19.
A common method used for the determination of material flow stress is the application of a compression test. At a low strain rate and deformation, the precise flow stress can be obtained in this method, but at a large level of deformation, the friction in the interface between the die and the specimen leads to inevitable bulging of the sample and thereby to inhomogeneous strain and stress. As a result, the flow-stress precision is affected because of the above-mentioned bulging. To reduce the error caused by inhomogeneous deformation, a new method combining compression tests with FEM simulation (C-FEM) is described in this paper. This method takes AISI 1006 and AISI 5140 as examples, and inputs their flow stress determined by compression tests into FEM programs. Then the flow stress is applied in the analysis of upsetting tests. On the basis of load–stroke curves determined by FEM simulation and compression tests, a target-function for evaluating flow-stress precision is set up. The flow stress direct from compression tests can be corrected by optimizing the target-function repeatedly, and as a result the precision of the material flow stress is improved. 相似文献
20.
Flow Behavior and Constitutive Model Using Piecewise Function of Strain for TC11 Alloy 总被引:2,自引:1,他引:1
针对TC11钛合金,提出了基于应变分段的Arrhenius双曲正弦模型,并进行热模拟压缩试验,分析了TC11钛合金高温流变行为及流变参数对流变应力的影响。采用分段函数的Arrhenius双曲正弦方法,在不同应变区域下求出不同的材料参数,得到了更为精确的本构模型。对比试验结果表明,模型具有很高的精度,并对比了模拟结果,表明模型是可靠的。 相似文献