Results 21 to 30 of about 152,103 (158)
ABSTRACT Bimetallic structures fabricated by laser powder bed fusion (LPBF) provide an effective strategy for achieving multifunctional integration, yet interfacial structural continuity and the role of lattice defects remain insufficiently understood.
Jinguo Ge, Shuo Yin
wiley +1 more source
本文用三点弯曲和四点弯曲试样,在K_Ⅱ/K_Ⅰ=0—14的范围内,对GC-4超高强度钢、30Cr2MoV中强度转子钢和稀土球墨铸铁进行了线弹性平面应变复合型脆断试验。结果表明:复合型裂纹的脆断开裂方向与现有的三种复合型理论符合较好;但是,复合型裂纹扩展阻力随K_Ⅱ/K_Ⅰ比值增加而增大,与现有复合型理论差别较大。本文从塑性区的形状、大小和裂纹顶端在开裂方向的应力状态等方面对此问题进行了分析并指出,现有理论关于复合型裂纹扩展阻力与变形特征无关的假设,对于具有一定塑性变形能力的金属材料,是不合适的 ...
杨成寿, 王自强, 高桦, 周爱华
core +2 more sources
针对一起500 kV断路器爆破片破裂事故,通过对破裂爆破片开展理化检验,发现故障爆破片材质为灰铸铁,表面有微孔,双侧用橡胶层密封保护,没有锈蚀,电镜分析表明材料脆性较大。通过更换同型断路器爆破片,比较新旧爆破片的性能,发现旧爆破片均有变形,大部分旧爆破片外侧橡胶层老化龟裂,导致爆破片进水锈蚀。通过开展爆破试验,发现部分旧爆破片爆破压力降低,但并不是锈蚀严重的样品。结果表明锈蚀并不是导致爆破片爆破压力下降的关键原因,该爆破片为平板型,铸铁材质,脆性较大,抗疲劳性能不足 ...
焦宗寒, 郑欣, 马宏明, 宋玉锋
doaj
ABSTRACT An ultra‐high as‐deposited tensile strength of 1408 MPa—the highest reported value for laser‐directed energy deposition (L‐DED) fabricated Ti2AlNb alloy—is achieved in this study. The as‐deposited microstructure consists of coarse B2 grains with a high density of fine acicular O phase precipitates within the grains, along with a brittle α2 ...
Ximiao He +7 more
wiley +1 more source
复合绝缘子断串及芯棒击穿事故会对输电线路的安全稳定运行构成严重的威胁。文中对2016年以来浙江省内发生的复合绝缘子断串及芯棒击穿故障案例进行统计分析,包括故障概况、产品情况、故障形态、性能试验、故障原因以及相关建议措施等。结果表明,2016年以来浙江省内共发生8起复合绝缘子断串及芯棒击穿故障,包括6起酥朽断裂、1起脆性断裂及1起芯棒击穿。其中,脆性断裂主要为端部密封不良,外部潮气进入,并在长期高场强作用下产生的应力腐蚀所致;酥朽断裂主要为芯棒—护套粘接不良,在受潮、放电 ...
周晨 +5 more
doaj
Simulating hydrogen embrittlement fracture based on phase field method
The phase field hydrogen embrittlement fracture model is improved by introducing tension-compression split of strain energy. The numerical formulas of the model are provided, besides, the coupling term of concentration field and displacement field is ...
CHEN Pengcheng +3 more
doaj +1 more source
ABSTRACT The inherent brittleness of hardmetals stems from the rigid covalent bond in the ceramic matrix and the sharp ceramic/metal interface, which restricts the nucleation and motion of dislocations. In this study, a novel strategy is proposed to activate significant dislocation behaviors in the WC matrix by employing a non‐equiatomic CoNiFeCr ...
Cheng Qian +9 more
wiley +1 more source
Abstract Chinese consumer demand for ivory threatens vulnerable African elephant populations, despite long‐standing efforts to combat the illegal wildlife trade. Behavioural science approaches have been proposed to address these systemic behaviours. However, their robust use remains uncommon in demand management interventions.
Molly R. C. Brown +3 more
wiley +1 more source
ABSTRACT Nb‐Si‐based superalloys are considered as the most potential candidate materials for nickel‐based superalloys due to the lower density and higher using temperature. Here, a type of stable Nbss/γNb5Si3 bi‐phases structure with a coherent interface has been successfully designed. Additionally, the Nbss and γNb5Si3 phases showcase the orientation
Xiao‐Wei Wang +6 more
wiley +1 more source
陶瓷、岩石和混凝土等非均质材料的准脆性损伤断裂,既不同于玻璃的理想脆性断裂,又有别于金属材料的韧性断裂。本研究建立了该类材料的微观断裂力学模型——广义梁链网模型~([1,2]),根据应力重分配的思想实现渐进失效的模拟。重点考虑了三个方面的问题:1.微结构预应力的影响~([3,4])。微结构预应力是指混凝土风干过程中基体与骨料间的非协调变形导致的初始非零应力场。研究表明,微结构预应力可显著提升材料的延展性,并且造成卸载后不可恢复的变形。2.惯性效应~([5,6])。在新裂纹生成的瞬间 ...
梁乃刚, 刘金兴
core +2 more sources

