Results 11 to 20 of about 3,386 (109)
Atom Probe Tomography‐Based Analysis of Residual Trace Elements in Advanced Metallic Materials
ABSTRACT Residual trace elements inherited from raw materials strongly influence the mechanical and environmental performance of advanced metallic alloys and recycling materials due to preferable boundary/interface segregation and resultant embrittlement effects, yet their parts per million level concentrations pose significant challenges to ...
Congcong Li +17 more
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ABSTRACT Nickel‐based superalloys (Ni‐based superalloys) have attracted extensive attention in laser additive manufacturing (LAM) due to their capability to directly fabricate complex and high‐performance structural components. However, the rapid melting and solidification inherent to LAM result in intense thermal cycling, which induces high residual ...
Tianxiang Lin +9 more
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对接焊缝为钢结构典型的焊缝形式,其位置处的裂纹和气孔型缺陷准确检测对于维护钢结构有着重要的意义,使用磁记忆检测技术对焊缝裂纹和气孔型缺陷进行定位时,传统的零点极值理论会由于焊接残余应力的影响,难以区分残余应力和焊接裂纹和气孔型缺陷所产生的磁信号,使其在实际检测中造成缺陷定位的误判和漏判,因此,从焊接裂纹和气孔型缺陷和残余应力所在区域磁信号产生机理的不同入手,开展考虑残余应力影响下的焊接裂纹和气孔型缺陷定位检测研究。首先对焊接残余应力与裂纹和气孔型缺陷产生磁信号的机理进行分析 ...
陈悦, 潘学豪, 邓淋方
doaj
ABSTRACT The thermal expansion mismatch between sapphire and Ti‐6Al‐4V (TC4) alloy has traditionally limited the shear strength of ceramic‐metal joints to ≤ 170 MPa. In this study, active brazing with Ag‐35.25Cu‐1.75Ti (wt%) leads to the formation of a dual‐function microstructure, wherein uniformly dispersed submicron Ti3(Cu,Al)3O particles embedded ...
Hairui Liu +13 more
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磁应变法近年来在工程结构残余应力检测方面得到了迅速发展,具有设备简单、操作方便等优点,能方便得到残余应力分布形式,但数值精度不高。采用热轧H形钢加载回弹试验制作了标准残余应力试件,利用磁应变法和盲孔法分别测试了残余应力。通过与有限元计算结果比较发现,盲孔法测得残余应力分布和数值均与计算结果吻合良好。磁应变法测得的残余应力分布正确,但数值随不同处理方法精度不同。研究了提高磁应变法数值精度的方法,得到了采用峰值残余应力处盲孔法数值为基准可有效提高测试精度的重要结论。
王嘉伟 +4 more
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ABSTRACT TiFe‐based hydrogen storage alloys have garnered significant attention because of their cost‐effectiveness, high hydrogen capacity, and favorable hydrogen absorption/desorption characteristics. However, practical application was limited by activation challenges and sensitivity to environmental poisoning.
Yuehai Li +8 more
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Restoration of monoculture in protected and marginal areas can be organized into two phases (1) identification and prioritization of restoration sites based on remote sensing or field survey then assessing degradation level, and (2) implementation of appropriate restoration interventions.
Liang Song +9 more
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根据已有残余应力分布模型对冷弯厚壁型钢典型截面进行了理论分析,得到残余应力对冷弯厚壁型钢轴压构件承载力的影响规律。在理论分析的基础上对不同厚度、不同宽厚比的Q235、Q345冷弯厚壁型钢进行有限元分析,得到不同长细比的各构件在考虑和不考虑残余应力两种情况下的轴压承载力,并研究残余应力对冷弯厚壁型钢长柱轴压承载力的影响。结果表明:残余应力对冷弯厚壁型钢轴压承载力的影响在长细比为90时达到最大,且对Q235钢的影响比Q345钢的影响略小 ...
李元齐, 李功文, 沈祖炎
doaj
冷成型钢截面上的残余应力可能是决定其性能和强度的一个重要因素。通过破坏性的试验方法对残余应力进行测量不仅费时,精度也很有限。本文提出了一个预测压弯成形薄壁截面上残余应力的有限元方法,该方法克服了实验室测量的缺点,提供了一个有力的工具来考察不同的成形参数对残余应力的大小和分布的影响,并因此可以对这些成形参数进行优化。在该方法中,通过解析的方法考虑了成卷和开卷的影响,并将得到的残余应力作为随后的冷弯过程有限元模拟的初始应力。经比较,本文方法的数值结果和实验室实测值吻合很好,证明了该方法的可行性和精度 ...
郭伟明, 滕锦光, 钟国辉
doaj
针对传统盲孔法仅能够测量钻孔深度范围内残余应力均值的缺陷问题,采用逐层钻孔法对14根不同焊接方式和径厚比的Q520高强焊接圆钢管进行纵向残余应力测试。基于实测数据,得到了高强焊接圆钢管截面纵向拉、压残余应力的数值大小、纵向残余应力分布模式以及在钻孔深度范围内的变化规律,研究了埋弧焊(submerged arc welding,简称SAW)、高频焊(high‑frequence welding,简称HFW)以及不同径厚比对截面纵向残余应力分布的影响。试验结果表明:纵向残余应力在钻孔深度范围内逐层减小 ...
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