T9I6形变热处理工艺对2519A铝合金组织、力学性能及抗弹性能的影响(英文)

借助金相显微镜、透射电镜、拉伸测试、抗弹性能测试等手段研究T9I6新型形变热处理对2519A铝合金组织、力学性能和抗弹性能的影响。经T9I6工艺处理的2519A铝合金,其屈服强度、抗拉强度、伸长率分别达到501 MPa、540 MPa、14%。30 mm厚的2519A-T9I6铝合金板材的极限穿透速度达715 m/s。弹坑侧壁组织随着弹孔深度的变化而变化。T9I6热处理工艺中的断续时效阶段是2519A铝合金性能提升的关键。低温下的时效使得GP区变得密集,从而使得后续相的析出也变得更为密集、细小。     

时效温度对大冷变形2519A铝合金组织与性能的影响

采用拉伸性能测试、显微硬度测试、扫描电镜和透射电镜观察等手段,研究了不同时效温度对50%冷变形2519A铝合金组织和力学性能的影响。结果表明:采用较大变形程度(50%)冷轧,再进行低温较长时间时效(140℃×6 h),可使2519A铝合金的强度得到显著提高(σb=551 MPa),同时其伸长率不低于7%;经冷变形的2519A铝合金,在稍高温度短时间(190℃×2 h)时效处理,将导致时效强化能力降低,但仍不低于常规时效处理(T6态:170℃×13 h)。     

T9I6热处理对2519A铝合金厚板厚向组织与性能的影响

采用扫描电镜、透射电镜、室温拉伸测试及疲劳性能测试等方法,研究T87和T9I6断续时效处理对51 mm厚2519A铝合金厚板厚向组织与性能的影响。结果表明：经T9I6断续时效处理后,2519A铝合金晶粒组织和析出相沿厚度方向分布不均匀。从表层到中间层,随着晶粒长径比的增加,粗大第二相和未固溶相体积分数也随之变大,时效析出相的体积分数随之降低;与T87态合金相比,2519A-T9I6合金晶内析出相的体积分数更大,且分布更均匀,其厚向屈服强度与抗拉强度较T87态分别提高50 MPa和90 MPa。同时,由于预时效处理后的中间层相对较软,故冷轧变形能够深入中间层,在加工硬化以及析出强化的共同作用下,T9I6合金厚向硬度整体提高,硬度不均匀性降低。在相同疲劳加载条件下,T9I6态厚向的疲劳寿命更高,疲劳极限较T87态提高了21 MPa。     

时效工艺对2519A铝合金力学性能及抗应力腐蚀开裂性能的影响

通过常温拉伸实验、慢应变拉伸应力腐蚀实验、极化曲线测试及透射电镜等研究了不同时效工艺对2519A合金的力学性能和抗应力腐蚀开裂性能的影响.结果表明:与传统的2519A-T87合金相比,再时效时间为19 h的2519A-T9I7合金同时具有优异的力学性能和良好的抗应力腐蚀开裂性能.这是由于2519A-T9I7合金在T9I...     

强变形工艺对2519A铝合金组织与性能的影响

通过硬度测试、拉伸性能测试、透射电镜观察等分析手段研究了不同强变形工艺下2519A铝合金的力学性能与微观组织。结果表明,经50%的冷轧变形和165 ℃人工时效后,2519A合金的力学性能明显提高,其抗拉强度、屈服强度和伸长率分别为522 MPa、468 MPa和8.5%。而在冷变形前添加165 ℃×2 h预时效处理,合金的力学性能进一步提高,其抗拉强度、屈服强度和伸长率分别达到535 MPa、497 MPa和8%。预时效处理可以提高合金中θ′相的密度,使析出相分布更加均匀,有助于提高合金的力学性能。     

二次时效对2519A铝合金组织与性能的影响

通过正交试验获得2519A铝合金优化的二次时效工艺,并通过硬度测试、拉伸测试、极化曲线分析、晶间腐蚀试验和透射电镜观察等方法对比不同时效状态样品的力学性能和耐蚀性能。结果表明:与等温时效相比,二次时效能提高2519A铝合金的屈服强度,同时改善合金的耐蚀性能,这是因为二次时效后晶内形成了细小弥散的θ″相,同时晶内的普遍脱溶使晶内基体与晶界无沉淀析出带(PFZ)的电位差减小。     

2519铝合金热轧板材抗应力腐蚀敏感性研究

以腐蚀强度指标Kσ和腐蚀伸长率指标Kδ评定合金的抗应力腐蚀敏感性，研究了2519铝合金热轧板材在T6、17和T8三种时效状态下的抗应力腐蚀敏感性。结果表明，2519铝合金热轧板材的抗应力腐蚀敏感性由高到低按118、17、T6工艺排序，而它们的力学性能按T6、T8、17的顺序排列。另外，测试了三种工艺状态下2519铝合金试样的恒电位极化曲线，发现合金的极化电阻越大时，其抗应力腐蚀敏感性越好。     

停放时间/时效延迟时间对6005A铝合金弯曲型材性能的影响

通过拉伸、硬度及导电率测试等方法,系统探究了6005A铝合金固溶冷却后停放时间对型材弯曲性能及时效延迟时间对合金型材性能的影响。研究表明,6005A铝合金固溶后停放48 h之内,合金的强度快速升高,抗拉和屈服强度分别从140.5 MPa和37 MPa升至207 MPa和96 MPa;硬度从43.6 HV升至66 HV。杯突值和加工硬化指数n值的变化指出,6005A铝合金最佳的固溶后停放时间不应超过24 h。时效延迟时间在3 h之内的铝合金的性能变化明显,抗拉强度和屈服强度从293.3 MPa和277 MPa下降至262 MPa和245 MPa,伸长率从15%降至12.6%,最佳的时效延迟时间应小于3 h;延迟时间超过10 d后,抗拉和屈服强度呈“断崖式”下降至256 MPa和231 MPa。     

冷轧与拉伸复合预变形对2519A铝合金板材应力腐蚀的影响(英文)

采用10-6s-1慢应变拉伸测试手段研究冷轧与拉伸复合预变形对2519A铝合金抗应力腐蚀开裂性能的影响。冷轧7%后再垂直拉伸3%的合金板材抗拉强度和应力腐蚀指数分别为481MPa和0.0429,与冷轧4%后再平行拉伸3%以及冷轧7%后再平行拉伸3%的合金板材相比表现出了更好的力学性能和抗应力腐蚀开裂性能。这主要是由于冷轧7%后再垂直拉伸3%在合金板材中生成了密度更高且分布更均匀的位错组织,使时效后合金板材晶内析出相细小、密集,晶界析出相不连续,晶界无沉淀析出带且较窄。     

2519A铝合金动能吸收能力与抗弹性能

采用分离式Hopkinson压杆(SHPB)装置进行了动态冲击试验,获得了名义应变速率为3500 s-1条件下2519A铝合金T87态、淬火态以及T87态与淬火态组合试样的真应力-应变曲线.通过对应力-应变曲线进行面积积分获得了试样单位体积吸收的动能值,用以比较不同处理状态试样的动能吸收能力.采用54式穿甲燃烧弹对20 mm 20 mm复合装甲板进行实弹打靶试验,以验证2519A铝合金动能吸收能力与抗弹性能的一致性,并运用TEM对侵彻弹坑边缘微结构特征进行分析.结果表明,2519A-T87态动能吸收能力最强,T87态与淬火态组合试样次之,淬火态试样最弱,打靶试验表明2519A合金的动能吸收能力与抗弹性能一致.     

2519A铝合金的动态力学性能及本构关系

为研究应变速率及温度对2519A铝合金流变应力的影响,对2519A铝合金进行动态力学性能测试及准静态拉伸实验,结合光学显微镜及透射显微电镜分析应变速率及温度对微观组织演化的影响。研究结果表明：2519A铝合金具有应变速率效应及温度敏感性。采用变量分离与非线性拟合方法对准静态及霍普金森压杆（SHPB）实验数据进行拟合,得到2519A铝合金的Johnson-Cook本构模型参数,曲线拟合与实验结果吻合较好,为力学性能的研究及抗弹性能有限元分析提供了参考。     

Effect of Y content on microstructure and mechanical properties of 2519 aluminum alloy

The effects of yttrium（Y） content on precipitation hardening, elevated temperature mechanical properties and morphologies of 2519 aluminum alloy were investigated by means of microhardness test, tensile test, optical microscopy（OM）, transmission electron microscopy（TEM） and scanning electron microscopy（SEM）. The results show that the tensile strength increases from 485 MPa to 490 MPa by increasing Y content from 0 to 0.10%（mass fraction） at room temperature, and from 155 MPa to 205 MPa by increasing Y content from 0 to 0.20% at 300 ~C. The high strength of 2519 aluminum alloy is attributed to the high density of fine 0＇ precipitates and intermetallic compound AICuY with high thermal stability. Addition of Y above 0.20% in 2519 aluminum alloy may induce the decrease in the tensile strength both at room temperature （20 ℃） and 300℃.     

Effects of Yb addition on microstructures and mechanical properties of 2519A aluminum alloy plate

The effects of Yb content on the microstructures and mechanical properties of 2519A aluminum alloy plate were investigated by means of tensile test,optical microscopy,transmission electron microscopy,scanning electron microscopy and X-ray diffractometer.The results show that addition of 0.17% (mass fraction) Yb increases the density of θ' particles of the 2519A alloy plate and reduces the coarsening speed rate of θ' phase at 300 ℃.Therefore,tensile strength is enhanced from 483.2 MPa to 501.0 MPa at room temperature and is improved from 139.5 MPa to 169.4 MPa at 300 ℃.The results also show that with the addition of 0.30% (mass fraction) Yb,the mechanical properties increase at 300 ℃ and decrease at room temperature.With Yb additions,the Al7.4Cu9.6Yb2 phase is found whilst the segregated phases of as-cast alloys along grain boundaries become discontinuous,thin and spheroidized.     

Effect of Cu on microstructure and mechanical properties of 2519 aluminum alloy

The effect of Cu on the microstructure and mechanical properties of 2519 aluminum alloy was investigated by means of tensile test, microhardness test, transmission electron microscopy, and scanning electron microscopy. The results show that when the content of Cu is less than 6.0%, the strength of 2519 aluminum alloy increases with the increase of Cu eontent; when the content of Cu is more than 6.0%, the strength of the alloy decreases. The hardening effect of the aged alloy is accelerated at 180℃ and the time to peak age is reduced, but the plasticity of the alloy gradually decreases with the increase of Cu content. However, the hardening effect of the aged alloy decreases with the increase of Cu as the content of Cu is over 6.0%. The optimal content of Cu of 2519 aluminum alloy is 6.0%, at which the alloy has best tensile strength and plasticity.     

Effect of secondary aging on microstructure and properties of cast Al-Cu-Mg alloy

To obtain better comprehensive properties of cast Al-Cu-Mg alloys, the secondary aging (T6I6) process (including initial aging, interrupted aging and re-aging stages) was optimized by an orthogonal method. The microstructures of the optimized Al-Cu-Mg alloy were observed by means of scanning electron microscopy and transmission electron microscopy, and the properties were investigated by hardness measurements, tensile tests, exfoliation corrosion tests, and intergranular corrosion tests. Results show that the S phase and θ′ phase simultaneously exist in the T6I6 treated alloy. Appropriately increasing the temperature of the interrupted aging in the T6I6 process can improve the mechanical properties and corrosion resistance of Al-Cu-Mg alloy. The optimal comprehensive properties (tensile strength of 443.6 MPa, hardness of 161.6 HV) of the alloy are obtained by initial aging at 180 °C for 2 h, interrupted aging at 90 °C for 30 min, and re-aging at 170 °C for 4 h.

     

超塑预处理对2024铝合金组织和性能的影响

采用三种工艺研究了超塑预处理对2024铝合组织和性能的影响.拉伸试验结果表明:超塑预处理后合金的力学性能明显提高,抗拉强度均在572 N/mm2以上,最高达到580 N/mm2,相应的伸长率也在9.1%以上.比2024铝合金的T62状态的抗拉强度(440 N/mm2)和伸长率(5%)分别提高32%和80%.但时效时间不少于60 min,合金的力学性能急剧降低.     

热处理对砂型铸造Mg-10Gd-3Y-0．5Zr镁合金微观组织和力学性能的影响

采用金相分析、SEM、硬度试验和拉伸试验等方法分析和测试砂型铸造 Mg-10Gd-3Y-0.5Zr 镁合金在T6态（固溶后空冷然后时效）下的显微组织和室温力学性能,讨论该合金的断裂机理。结果表明,砂铸Mg-10Gd-3Y-0.5Zr合金在225℃和250℃时效下的最优T6热处理工艺分别为（525℃,12 h＋225℃,14 h）和（525℃,12 h＋250℃,12 h）。峰时效下T6态Mg-10Gd-3Y-0.5Zr合金主要由α-Mg＋γ＋β′相组成,2种峰时效热处理工艺下合金的抗拉强度、屈服强度和伸长率分别为339.9 MPa、251.6 MPa、1.5%及359.6 MPa、247.3 MPa、2.7%。在不同热处理工艺下Mg-10Gd-3Y-0.5Zr合金断裂的类型不同,峰时效态合金的断裂方式为穿晶准解理断裂。     

Effect of thermomechanical treatment on the microstructure,phase composition,and mechanical properties of Al–Cu–Mn–Mg–Zr alloy

The effect of the thermomechanical treatment on the microstructure, phase composition, and mechanical properties of heat-treatable AA2519 aluminum alloy (according to the classification of the Aluminum Association) has been considered. After solid-solution treatment, quenching, and artificial aging (T6 treatment) at 180°C for the peak strength, the yield stress, ultimate tensile strength, and elongation to failure are ~300 MPa, 435 MPa, and 21.7%, respectively. It has been shown that treatments that include intermediate plastic deformations with degrees of 7 and 15% (T87 and T815 treatments, respectively) have a significant effect on the phase composition and morphology of strengthening particles precipitated during peak aging T8X type, where X is pre-strain percent, treatments initiate the precipitation of significant amounts of particles of the θ′- and Ω-phases. After T6 treatment, predominantly homogeneously distributed particles of θ″-phase have been observed. Changes in the microstructure and phase composition of the AA2519 alloy, which are caused by intermediate deformation, lead to a significant increase in the yield stress and ultimate tensile strength (by ~40 and ~8%, respectively), whereas the plasticity decreases by 40–50%.