双级时效对1420铝锂合金超塑性的影响

采用金相、透射电镜、高温拉伸等检测手段研究了双级时效对1420铝锂合金组织及超塑性的影响,结果表明:与单级时效相比,双级时效处理得到分布更均匀、体积分数更大的析出相粒子.双级时效经过轧制和再结晶退火后,得到的晶粒尺寸为8～12μm;500℃条件下8×10-4s-1超塑性伸长率达到860%.第一级低温时效先在基体形成较均匀的细小粒子,这些粒子不仅在晶界,也在晶内大量析出.在高温时效时,这些粒子长大形成分布均匀,体积分数大的析出相粒子.     

退火工艺对Ti80合金组织与性能的影响

通过不同的热处理制度研究了退火工艺对Ti80合金板材组织和性能的影响。结果表明,退火工艺对Ti80合金的力学性能的影响较大,在退火温度为900℃时,随着保温时间的延长,室温抗拉强度先升后降;在退火时间均为2 h的情况下,随着退火温度从850℃提高到950℃,初生α相的含量逐渐减少,β相的含量逐渐增多,初生α相的晶粒尺寸没有明显的变化。     

二次烧结温度对放电等离子烧结制备Ti2AlNb合金显微组织和力学性能的影响

采用高能球磨法和放电等离子烧结（SPS）技术制备了Ti₂AlNb合金;利用X射线衍射仪（XRD）、扫描电镜（SEM）和万能拉伸试验机研究了二次烧结温度对合金显微组织和力学性能的影响。结果表明：不同二次烧结温度所制备的Ti₂AlNb合金组织均由B2相、等轴状α₂相和针状O相组成。二次烧结温度在900～950℃范围内时,针状O相呈第二相在B2基体相内部析出,等轴状α₂相团聚在B2基体相之间;二次烧结温度在1 000～1 100℃范围内时,等轴状α₂相分布不再集中,数量逐渐减少。二次烧结温度为1 000℃所制备的Ti₂AlNb合金拥有良好的力学性能,室温抗拉强度达到309 MPa,维氏硬度可达466.5 HV。     

Formation mechanism of gradient-distributed particles and their effects on grain structure in 01420 Al-Li alloy

Fine-grained 01420 Al-Li alloy sheets were produced by thermo-mechanical processing based on the mechanism of particle stimulated nucleation of recrystallization. The thermo-mechanically processed sheets were observed to contain layers of different microstructures along the thickness. The precipitate behavior of the second phase particles and their effects on the distribution of dislocations and layered recrystallized grain structure were analyzed by optical microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and X-ray diffractometry（XRD）. The formation mechanism of the gradient particles was discussed. The results show that after aging, a gradient distribution of large particles along the thickness is observed, the particles in the surface layer（SL） are distributed homogeneously, whereas those in the center layer（CL） are mainly distributed parallel to the rolling direction, and the volume fraction of the particles in the SL is higher than that in the CL. Subsequent rolling in the presence of layer-distributed particles results in a corresponding homogeneous distribution of highly strained regions in the SL and a banded distribution of them in CL, which is the main reason for the formation of layered grain structure along the thickness in the sheets.     

钛合金J-C动态本构参数高精度分析及抗弹性能研究

利用\"材料J-C本构参数及损伤模型参数测定系统\"软件,通过聚类全局优化(CGO)法获得一种近α型钛合金材料的J-C动态本构参数,规避了传统测定方法计算量大、方法复杂,且无法体现参数关联性等缺点,通过钛合金靶板的抗弹性能测试,利用J-C本构参数,采用商业动力学计算软件AUTODYN对枪击试验完成了模拟,模拟的各项结果与试...     

热处理对TA15钛合金棒材冲击性能的影响

研究了热处理制度对TA15钛合金棒材显微组织的影响,并测试了热处理后试样的冲击性能.结果表明:通过调整退火温度及保温时间,可改变合金的显微组织,提高TA15钛合金的冲击性能.TA15钛合金在初生a相的形状和大小基本相同的情况下,次生a相的形状和大小对冲击韧度的影响比较大.次生a为条状时的冲击值明显高于次生仅为圆形或短棒状时的冲击值.经810℃×2h,AC热处理后,可获得冲击性能良好的TA15钛合金棒材,并且冲击性能提高了35%.     

基于晶体取向q值计算再结晶分数的改进方法

以大变形高纯铝在300℃的退火试样为例,提出了一种基于EBSD数据中q值计算再结晶分数的改进方法,该方法通过分离不同取向的q值数据,对于不同的取向数据分别采用Tarasiuk提出的q值积分算法计算再结晶分数,即与完全再结晶状态及变形态的q值数据进行对比并积分计算,再按各取向的再结晶分量权重求和得出总体的再结晶分数.结果...     

Evolution of grain structure in AA2195 A1-Li alloy plate during recrystallization

The evolution of the grain structures in AA2195 Al-Li alloy plate warm-rolled by 80% reduction during recrystallization annealing at 500℃ was investigated by electron backscatter diffraction, scanning electron microscopy and transmission electron microscopy. It is found that the elongated grain structures are caused by the lamellar distribution of recrystaUization nucleation sites, being lack of large second phase particles （〉 1μm）, and dispersive coherent particles （such as δ′ and β′concentrated in planar bands. The recrystallization process may be separated into three stages： firstly, recrystallization nucleation occurs heterogeneously, and the nuclei are concentrated in some planar zones parallel to rolling plane. Secondly, the grain boundaries interacted with small particles concentrate in planar bands, which is able to result in the elongated grain structures. The rate of the grain growth is controlled by the dissolution of these small particles. Thirdly, after most of small particles are dissolved, their hindrance to migration of the grain boundaries fades away, and the unrecrystallized zones are consumed by adjacent recrystallized grains. The migration of high angle grain boundaries along normal direction leads a gradual transformation from the elongated grains to the nearly equiaxed, which is driven by the tension of the grain boundaries.     

锻造工艺对Ti-6321合金棒材显微组织与力学性能的影响

研究了不同锻造工艺对Ti-6321合金棒材组织与力学性能的影响。结果表明:Ti-6321合金棒材经常规锻造后为等轴组织,经近β锻造后为双态组织,经β锻造后为网篮组织;双态组织不仅具有与等轴组织和网篮组织相当的强度和塑性,而且冲击韧性可达到850 kJ/m2以上,明显高于等轴组织和网篮组织。