Effect of Scandium and Zirconium on Mechanical and Exfoliation Corrosion Properties of Al-Mg-Mn Alloys

To quest for the best combination of mechanical properties and exfoliation corrosion resisting property of Al-Mg-Mn base alloys, and to seek after the effect of Sc and Zr on mechanical and exfoliation corrosion properties of Al-Mg-Mn alloys, comparative research technique was used, the mechanical properties of Al-Mg-Mn alloys with and without minor Sc and Zr treated by different annealing were measured, the degrees of exfoliation corrosion for these alloys through accelerated exfoliation corrosion test were evaluated, and polarization curves of these alloys were measured, too. The micro-morphologies of corrosion specimens were observed by SEM and the corrosion product was analyzed using EDS. Optical microscope and TEM were used, the relationship between their microstruc-tures and mechanical properties, exfoliation corrosion resisting property was investigated, and the results show that the addition of minor Sc and Zr can enhance the strength greatly and also improve the combination of strength and plasticity. Moreover, the addition of minor Sc, Zr does not cause appreciable decrease of exfoliation corrosion resisting property, the Al-Mg-Mn-Sc-Zr alloy annealed at 350 ℃ for 1 h has excellent combination of mechanical properties and exfoliation corrosion resisting property, the satisfied combination of mechanical properties nad exfoliation corrosion resisting property can be obtained by means of adding minor Sc and Zr, decreasing the content of Mn, and adopting reasonable annealing practice.

Effect of minor Sc and Zr on superplasticity of Al-Mg-Mn alloys

The effect of Sc and Zr on the superplastic properties of Al-Mg-Mn alloy sheets was investigated by control experiment. The superplastic properties and the mechanism of superplastic deformation of the two alloys were studied by means of optical microscope, scanning electronic microscope and transmission electron microscope. The elongation to failure of Al-Mg-Mn-Sc-Zr alloy is larger than that of Al-Mg-Mn alloy at the same temperature and initial strain rate. The variation of strain rate sensitivity index is similar to that of elongation to failure. In addition, Al-Mg-Mn-Sc-Zr alloy exhibits higher strain rate superplastic property. The activation energies of the two alloys that are calculated by constitutive equation and linear regression method approach the energy of grain boundary diffusion. The addition of Sc and Zr decreases activation energy and improves the superplastic property of Al-Mg-Mn alloy. The addition of Sc and Zr refines the grain structure greatly. The main mechanism of superplastic deformation of the two alloys is grain boundary sliding accommodated by grain boundary diffusion. The fine grain structure and high density of grain boundary, benefit grain boundary sliding, and dynamic recrystallization brings new fine grain and high angle grain boundary which benefit grain boundary sliding too. Grain boundary diffusion, dislocation motion and dynamic recrystallization harmonize the grain boundary sliding during deformation.

Effect of Sc and Zr on the in-plane anisotropy of Al-Mg-Mn alloy sheets

The Al-Mg-Mn alloy sheets with and without trace Sc and Zr were investigated by means of tensile test,X-ray diffraction,optical microscope,and transmission electron microscope.The indexes of in-plane anisotropy(IIPA)of their tensile mechanical properties were calculated and their inverse pole figures were obtained by Harris method.The two alloy sheets have the same law of in-plane anisotropy and remarkable in-plane anisotropy of mechanical properties,and the IIPA of the alloy sheet with Sc and Zr is bigger than that of the alloy sheet without Sc and Zr.The relationships of the in-plane anisotropy and the anisotropy of the crystallographic texture were analyzed based on the model of monocrystal.It is the common action of the anisotropy of crystallography and microstructures that causes the in-plane anisotropy of their mechanical properties,but the major cause is the{110}〈112〉crystallographic texture.The trace Sc and Zr can promote the formation and stabilization of the{110}〈112〉texture,inhibit the formation of the{100}〈001〉texture,and increase the in-plane anisotropy of the alloy sheet containing trace Sc and Zr.

Effect of Sc and Er additions on superplastic ductilities in Al-Mg-Mn-Zr alloy

The superplasticity of Al-6Mg-0.4Mn-0.25Sc-0.12Zr and Al-6Mg-0.4Mn-0.25Er-0.12Zr(mass fraction,%)alloys sheet was investigated,and the effect of Sc and Er was discussed.The results show that the superplastic ductilities of Al-Mg-Mn-Sc-Zr alloy was higher than that of Al-Mg-Mn-Er-Zr alloy at a wide temperature range of 400-540°C and high strain rate range of1.67×10-4-1.67×10-1 s-1.A maximum elongation 673%is obtained at 520°C and 1.67×10-3 s-1 in the Sc-containing alloy;while the Er-containing alloy only gets a maximum elongation 253%at 520°C and 1.67×10-3 s-1.Moreover,the average stress exponent of Sc-containing alloy is about 2.84,which is smaller than that of Er-containing alloy(3.64).Besides,the activation energies of the Sc-containing and Er-containing alloy are 84.8 k J/mol and 87.2 k J/mol,respectively.It is indicated that grain boundary sliding is the dominant mechanism during tensile deformation.According to microstructure examination,the better superplasticity of Sc-containing alloy may be attributed to the presence of Al3_(Sc,Zr)dispersoids,which can inhibit recrystallization and grain growth effectively.

微量Sc和Zr对Al-Mg-Mn合金组织与力学性能的影响

采用活性熔剂保护熔炼、水冷铜模激冷铸造制备Al-5.8Mg-0.4Mn和Al-5.8Mg-0.4Mn-0.25Sc-0.1Zr(质量分数,%)两种合金铸锭。合金铸锭经热轧中间退火冷轧成2 mm薄板;研究稳定化退火及微量Sc和Zr对Al-Mg-Mn合金组织与性能的影响。结果表明:在Al-Mg-Mn合金中加入微量Sc和Zr后形成大量弥散的Al3(Sc,Zr)粒子,这些粒子对位错和亚晶界具有强烈的钉扎作用,能明显提高合金的抗再结晶能力和室温力学性能;Al-Mg-Mn-Sc-Zr合金板材经300℃退火1 h后可获得最佳综合力学性能,其σb、σ0.2与δ分别为436 MPa、327 MPa和16.7%。

Al-Mg-Mn-Sc-Zr合金搅拌摩擦焊接头显微组织、力学性能及腐蚀性能

采用硬度测试、金相显微、透射电镜、慢应变速率拉伸、扫描电镜和极化曲线对2 mm厚Al-Mg-Mn-Sc-Zr冷轧-退火板材搅拌摩擦焊接头的显微组织、力学性能及腐蚀性能进行了研究。结果表明:焊接接头的硬度相比母材有所降低,硬度最低值出现在前进侧搅拌区与热机影响区的交界处;焊接接头在空气中和3.5%Na Cl(质量分数)溶液中的抗拉强度和伸长率均低于母材的,且应力腐蚀敏感性增加。此外,在焊接接头中,热机影响区是耐蚀性最差的区域,但是在空气和3.5%Na Cl溶液中的拉伸试样均断裂在厚度最薄的搅拌区而不是耐蚀性最差的热机影响区,可见应力腐蚀对试样断裂的影响有限,说明Al-Mg-Mn-Sc-Zr合金搅拌摩擦焊接头具有较好的抗应力腐蚀性。

Comparison of FSW and TIG welded joints in Al-Mg-Mn-Sc-Zr alloy plates

In order to study the welding process,microstructure and properties of Al-Mg-Mn-Sc-Zr alloy,comparative methods of friction stir welding（FSW） and tungsten inert gas（TIG） were applied to the two conditions of this alloy,namely hot rolled plate and cold rolled-annealed plate.The relationships between microstructures and properties of the welded joints were investigated by means of optical microscopy and transmission electron microscopy.Compared with the base metal,the strength of FSW and TIG welded joints decreased,and the FSW welding coefficients were higher than the TIG welding coefficients.The loss of substructure strengthening and a very little loss of precipitation strengthening of Al3（Sc,Zr） cause the decreased strength of FSW welded joint.But for the TIG welded joint,the disappearance of both the strain hardening and most precipitation strengthening effect of Al3（Sc,Zr） particles contributed to its softening.At the same time,the grains in weld nugget zone of FSW welded joints were finer than those in the molten zone of TIG welded joints.

Al-Mg-Mn和Al-Mg-Mn-Sc-Zr合金的再结晶

研究了Al-Mg-Mn和Al-Mg-Mn-Sc-Zr合金冷轧后在不同退火温度下合金的组织和性能的变化。结果表明,与不添加钪和锆的合金相比,复合添加0.4%Sc(质量分数)和Zr能使Al-Mg-Mn合金的再结晶开始温度提高120℃左右。添加微量Sc和Zr合金没有明显再结晶终了温度,在接近熔点时显微组织仍是加工态纤维组织。Sc,Zr复合添加形成的纳米级的二次Al3(Sc,Zr)相质点,对位错和亚晶界有强烈的钉扎作用,再结晶难以形核和长大,从而有效地抑制冷轧后退火过程中的再结晶。

Sc与Zr对Al-Mg-Mn合金力学性能和剥落腐蚀性能的影响

为了寻找Al-Mg-Mn合金力学性能和耐剥蚀性能的最佳组合,采用对比法探索Sc和Zr对Al-Mg-Mn合金力学性能和剥落腐蚀性能的影响,测定了含与不含微量Sc和Zr的Al-Mg-Mn合金板材在不同退火态的力学性能和剥落腐蚀性能,测量了它们的极化曲线。采用扫描电镜观察了合金的腐蚀微观形貌、用能谱仪分析了腐蚀产物的成分。采用光学显微镜和透射电子显微镜分析了合金的显微组织和力学性能、剥落腐蚀性能之间的关系。结果表明:添加微量Sc和Zr能显著提高Al-Mg-Mn合金强度,改善合金强度和塑性的配合,而且Sc和Zr的添加没有引起合金耐剥蚀性能的明显下降。经过350℃/1h退火的Al-Mg-Mn-Sc-Zr合金具有优良的力学性能和耐蚀性能组合。可通过添加微量Sc,Zr,减少Mg的含量,选择合理的退火工艺,使该类合金的力学性能和耐剥蚀性能达到理想组合。

Sc含量对Al-Mg-Mn合金板材组织与性能的影响

采用半连续铸造-轧制技术制备了两种Sc质量分数含量为0.25%和0.10%的Al-Mg-Mn合金薄板,研究了稳定化退火工艺对两种不同Sc含量合金板材拉伸力学性能、剥落腐蚀性能和显微组织的影响。结果表明,两种合金冷轧板材稳定化退火过程中有相同的组织、性能变化规律,即随着退火温度升高,板材强度稍有下降而塑性升高,表现出很强的抗退火软化的能力,其中低Sc含量合金拉伸性能略低于高Sc含量合金的;其次,随退火温度的升高,板材抗剥落腐蚀的能力也表现出相同规律性的变化,200℃1 h左右退火时剥落腐蚀最严重,随着退火温度升高,抗腐蚀性能提高;两种合金冷轧板材在300℃1 h稳定化退火可以获得较好的综合拉伸力学性能和腐蚀性能,在此条件下,低Sc含量的合金板材抗拉强度、屈服强度和伸长率仍然分别达到437 N/mm2、340 N/mm2和16.3%,有很好的开发应用前景。

Enhancing Na^(+) diffusion dynamics and structural stability of O3-NaMn_(0.5)Ni_(0.5)O_(2)cathode by Sc and Zn dual-substitution

Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural stability of NaMN was investigated.The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na^(+) diffusion channels and weaken the Na—O bonds,thereby facilitating the diffusion of sodium ions.Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material.The dual-substituted NaMn_(0.5)Ni_(0.4)Sc_(0.04)Zn_(0.04)O_(2)(Na MNSZ44)cathode delivers impressive cycle stability with capacity retention of 71.2%after 200 cycles at 1C and 54.8%after 400 cycles at 5C.Additionally,the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability,showing capacity retention of 64.1%after 250 cycles at 1C.These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na^(+) diffusion dynamics and structural stability of NaMN.

Supply Chain Management Analysis and Design for a Variety of Economic Scenarios, Including Data and System Administration

Due to the rapid progress of information technology, organizations anticipate significant changes in the planning, scheduling, and optimization aspects of operation and supply chain management (SCM) shortly. Two primary types of risk have an impact on supply chain management and design. The first group deals with the difficulties in matching supply and demand, whereas the second group deals with disruptions to regular business operations. The essay offers a theoretical framework that combines the cooperative efforts of risk assessment and mitigation, which are critical for effectively handling potential supply chain interruptions. This content provides insightful viewpoints on the strategic resources and operational structure needed to improve organizational success. We utilized the partial least squares (PLS) method to address the problem of multicollinearity and measurement mistakes in examining cause-and-effect constructs. The statistical method, Least Squares (PLS), used in structural equation modeling, is based on partial variance. The Partial Least Squares (PLS) strategy uses a two-stage estimate procedure to calculate weights, loadings, and route estimations. Initially, several simple and complex regressions were performed with the provided model. The procedure was repeated until a solution was found, resulting in a set of weights used to determine the latent variable scores. In the second step, non-iterative PLS regression yields loadings, path coefficients, mean scores, and location parameters. According to the structural study, implementing Sustainable Supply Chain Management (SSCM) can significantly improve a business’s operational and financial performance. The findings offer a comprehensive understanding of several elements of supply chain management (SSCM), including information systems, organizational configurations, supply chain network architecture (SCND), and supply chain strategy (SCS). The supply chain is essential for effectively moving goods over great distances and encouraging cooperation between parties. Therefore, these connections are established precisely, quickly, and cheaply via a knowledgeable and efficient supply chain. Two key components are necessary for a supply chain (SC) to be successful: efficient collaboration and the smooth integration of information-sharing platforms.

Al-Mg-Mn-Sc-Zr合金中Al3(Scx,Zr1-x)粒子的形成机制研究

用水冷铜模激冷铸造制备Al-5.8Mg-0.4Mn-0.25Sc-0.1Zr合金。用透射电镜(TEM)、扫描电镜(SEM)和金相显微镜(OM)研究合金中Al3(Scx,M1-x)第二相粒子的存在形式和形成机制。结果表明:Al-5.8Mg-0.4Mn-0.25Sc-0.1Zr合金在急冷铸造条件下,合金中的Sc和Zr主要以固溶形式存在于α(Al)基体中,透射电镜和扫描电镜下很难观察到这些粒子存在。初生Al3(Scx,M1-x)粒子对铸态晶粒具有细化作用,晶粒尺寸可细化到10~20μm。铸态合金经550℃退火20 h后析出大量次生Al3(Scx,M1-x)粒子,这些粒子呈内部富Sc,外部富Zr的复合结构。该结构的形成一方面是由于Sc在铝合金基体中的原子扩散速率比Zr大;另一方面,通过形成这样的结构可降低界面能。

用于MIMO SC-FDE系统逼近分集接收界的迭代检测算法

为了提高MIMO SC-FDE系统的检测可靠性、降低系统复杂度,提出一种新的迭代干扰消除检测算法,并推导出分集接收界作为评价算法性能优劣的依据.该检测算法采用基本的线性均衡算法提供初始值,在迭代中尽量消除层间干扰,利用空间分集增益逐步提高检测可靠性.结果表明,该算法在4QAM调制方式下,E b/N 0为9 dB时逼近分集接收界;在16QAM调制方式下,E b/N 0为16 dB时逼近分集接收界.该算法一轮迭代的计算复杂度与发射天线的数目成线性关系,天线规模为3×3以上时算法复杂度低于V-BLAST.因此,所提算法适用于天线规模数大于等于3、调制进制数大于等于4的系统中,在倾向于采用large MIMO系统的5G及后5G时代具有高效性和实用性.

Effect of homogenization treatment on microstructure and properties of Al-Mg-Mn-Sc-Zr alloy

The effect of homogenization on the hardness,tensile properties,electrical conductivity and microstructure of as-cast Al-6Mg-0.4Mn-0.25Sc-0.12Zr alloy was studied.The results show that during homogenization as-cast studied alloy has obviously hardening effect that is similar to aging hardening behavior in traditional Al alloys.The precipitates are mainly Al3(Sc,Zr)and Al6Mn.When homogenization temperature increases the hardness peak value is declined and the time corresponding to hardness peak value is shortened.The electrical conductivity of the alloy monotonously increases with increasing homogenization temperature and time.The decomposition of the supersaturated solid solution containing Sc and Zr which is formed during direct chilling casting and the precipitation of Al3(Sc,Zr)cause hardness increasing.The depletion of the matrix solid solubility decreases the ability of electron scattering in the alloy,resulting in the electrical conductivity increased.Tensile property result at hot rolling state shows that the optimal homogenization treatment processing is holding at 300-350 ℃ for 6-8 h.

Evaluation of pitting corrosion of Al-Mg-Mn-Sc-Zr alloy in EXCO solution by EIS

In order to evaluate the degree and severity of Al-Mg-Mn-Sc-Zr alloy in exfoliation corrosion(EXCO) solution quickly and nondestructively, electrochemical impedance spectroscopy(EIS) technique was employed. The Al-Mg-Mn-Sc-Zr alloy suffers pitting corrosion in the EXCO solution. During pit incubation, the Nyquist diagram is composed of a depressed capacitive arc at high-mediate frequency and an inductive arc at low frequency. The inductive arc fades with immersion time, and the beginning of pitting corrosion and the appearance of two capacitive arcs have simultaneity. During pit propagation, the Nyquist diagram is composed of two overlapped capacitive arcs. As time goes on, two time constants are more clearly distinguished. The high frequency and low frequency capacitive arc are aroused by passive surface and new interface, respectively. An equivalent circuit is designed to fit EIS, and the experimental results and the fitted results have good correspondence. The degree and severity of pitting corrosion can be obtained by the features of EIS and comparing the fitted values of parameters at different times.

Al-Mg-Mn-Sc铸态合金退火行为研究

通过水冷铜模急冷铸造法制备了Al-5.5Mg-0.4Mn-0.25Sc合金,研究了该铸态合金在不同退火温度下的硬度变化,并通过金相显微镜和透射电镜探讨合金中Al_(3)Sc粒子的存在形式和形成机理。结果表明:添加质量分数为0.25%的Sc对铸态合金晶粒组织的细化并没有产生太大的贡献,晶粒细化是由于快速凝固技术所带来的作用,在高的冷却速率下,合金中较难发现初生Al_(3)Sc粒子的存在。退火温度对于合金硬度有显著影响,在低的温度下退火时,合金硬度变化较慢,需较长时间才出现硬度峰值;而在较高温度下退火时,合金硬度峰值平台出现需要时间较短,但随着退火时间延长硬度迅速下降。在所测试的退火温度中,300℃下呈现出较好的硬度曲线,具有较高的硬度峰值平台且能维持较长时间不下降。退火过程中合金硬度的变化与次生Al_(3)Sc粒子的析出密切相关,退火温度较低时次生Al_(3)Sc粒子析出不充分、粒径较小,对晶界、亚晶界和位错的钉扎作用较弱;而退火温度太高,Al_(3)Sc粒子发生粗化,导致合金性能变差。

Sc、Zr对Al-Mg-Mn合金再结晶行为及内耗性能的影响

为了研究微量Sc、Zr在Al-Mg-Mn合金中的作用,采用铸锭冶金方法制备了Al-6.0Mg-0.5Mn-(Sc、Zr)合金,通过光学显微镜、显微硬度、透射电镜组织观察和低频扭摆法测量内耗方法研究了微量Sc、Zr对Al-6.0Mg-0.5Mn的组织、再结晶行为及内耗性能的影响.研究表明:添加质量分数为0.21%Sc和0.15%Zr可显著细化Al-6.0Mg-0.5Mn合金铸态组织;粒状Al3Sc1-xZrx相对位错、晶界有强烈钉扎作用,抑制合金再结晶;冷变形后的Al-6.0Mg-0.5Mn-0.21Sc-0.15Zr合金的内耗表现出非线性特征,频率越低或温度越高,合金内耗Q-1越大.在频率为1Hz、应变振幅为4.6×10-5下,冷变形Al-6.0Mg-0.5Mn-0.21Sc-0.15Zr合金升温Q-1-T曲线上在326℃时产生内耗峰,该峰可由Al3Sc1-xZrx沉淀粒子与位错脱钉机制解释.微量Sc、Zr可以细化Al-Mg-Mn合金组织,抑制合金的再结晶,导致合金在升温Q-1-T曲线上产生内耗峰.

基于Sophon SC5+芯片构架的行人搜索算法与优化

传统的基于深度神经网络的行人搜索算法计算量大,在大规模部署时搜索性能低,导致算法在落地应用于硬件和预算有限的终端时面临成本高、速度慢的难题。针对以上问题,提出一种基于Sophon SC5+高性能推理芯片的行人检测与重识别算法,从算法到硬件自上而下地优化深度学习的效率。首先,利用轻量化的Ghost模块替换YOLOv5s的主干网络,从而大幅度降低模型的参数和计算量;其次,融入CBAM注意力机制,以增强算法的特征学习能力,并提高检测精度;然后,将中心损失约束和Non-local注意力机制加入行人重识别模块,并结合中心约束三元组损失和附加间隔交叉熵损失优化模型,以提升行人重识别算法性能;最后,基于Sophon SC+量化行人检测模型和行人重识别模型并生成最终的推理模型。在Market-1501与DukeMTMC-ReID数据集上的实验结果表明,相较于YOLOv4-tiny、ACRN、SVDNet等主流算法,行人检测算法与行人重识别算法的平均精度均值(mAP)至少提高了43.8和25.7个百分点。基于Sophon SC5+芯片实现int8量化后,所提算法的mAP虽然减小了1.7个百分点,但模型大小减小了74.4%,能够在大规模、城市级行人搜索系统中落地使用。

退火工艺对Al-Mg-Mn合金力学性能及腐蚀性能的影响

对Al-Mg-Mn合金挤压型材进行不同工艺退火,探究退火工艺对Al-Mg-Mn合金挤压型材力学性能及腐蚀性能的影响。研究结果表明:Al-Mg-Mn合金挤压型材在退火后,抗拉强度、屈服强度及硬度均下降,伸长率提高,耐腐蚀性能有所提升;当退火温度升高到380℃时,挤压型材表面几乎没有明显的剥落腐蚀产物及晶间腐蚀凹坑,仅有极其少量的表面点蚀,具有较好的耐腐蚀性能;综合考虑Al-Mg-Mn合金挤压型材的力学及腐蚀性能,最佳退火温度为380℃,保温时间为2 h。