今日更新:Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇
A new test for characterization of interlaminar tensile strength of tape-laminate composites
Fisher John, Czabaj Michael W.
doi:10.1016/j.compositesa.2023.107868
表征胶带层压复合材料层间拉伸强度的新试验
Interlaminar tensile strength (ZT) is an important property of polymer matrix composites used for material screening, failure analysis, and design. Current methods for determining ZT suffer from drawbacks that prevent an unambiguous measurement of this property. This study proposes a new flexure-based specimen, previously used to measure intralaminar tensile strength (YT), which allows for a straightforward characterization of ZT. The proposed test is used to measure both ZT and YT of two microstructurally distinct carbon/epoxy systems. Overall, the experimental data demonstrates that the new test provides a reliable measure of ZT that is independent of the specimen manufacturing method. Importantly, a direct comparison between ZT and YT demonstrates that ZT tends to be lower than YT . Although no direct links between lower values of ZT and the specimen microstructure are discovered, this effect is likely influenced by the presence and location of resin-rich regions relative to the tensile stresses.
层间拉伸强度(ZT)是聚合物基复合材料的一项重要性能,用于材料筛选、失效分析和设计。目前测定 ZT 的方法存在一些缺陷,无法对该特性进行明确测量。本研究提出了一种新的基于挠曲的试样,这种试样以前用于测量层内拉伸强度(YT),可直接表征 ZT .所提议的测试可用于测量 ZT 和 YT 的 ZT 和 YT。总之,实验数据表明,新测试可提供可靠的 ZT 测量值,且不受试样制造方法的影响。 与试样制造方法无关。重要的是,直接比较 ZT 和 YT 之间的直接比较表明,ZT 往往低于 YT .虽然没有发现较低的 ZT 值与试样的微观结构有直接联系,但这种影响很可能受到树脂的存在和位置的影响。和试样微观结构之间没有直接联系,但这种影响很可能受到相对于拉伸应力的富树脂区域的存在和位置的影响。
Fabrication of TiB whiskers reinforced Ti6242 matrix composites by direct laser deposition: Powder preparation, microstructure and mechanical property
Li Lian, Ma Panpan, Zhang Ling, Tan Hua, Li Miaoquan
doi:10.1016/j.compositesb.2023.111068
用激光直接沉积法制造 TiB 晶须增强 Ti6242 基复合材料:粉末制备、微观结构和机械性能
Direct laser deposition (DLD) technique has great potential in manufacturing titanium matrix composites (TMCs) components with complicated shape. The TiB whiskers reinforced Ti6242 matrix composites were fabricated from the premixed TiB2/Ti6242 powders via DLD technique. Quantitative characterization of the extent of mixing uniformity and the deformation rate of the ball milled TiB2/Ti6242 powders was performed so as to select the optimal ball milling parameters. The TiB2/Ti6242 powders with two different weight fractions of TiB2 (2 wt%TiB2/Ti6242 and 5 wt%TiB2/Ti6242) were used to obtain different distributions of TiB whiskers in the composites due to the change in the solidification path in DLD process. The TiB whiskers in the TMCs-Ⅰ obtained from the 2 wt%TiB2/Ti6242 powders exhibited a discontinuous network structure following solidification in hypoeutectic zone, while the TiB whiskers were randomly distributed in the TMCs-Ⅱ obtained from the 5 wt%TiB2/Ti6242 powders due to the solidification in hypereutectic zone. In comparison with the DLDed Ti6242, the α colonies and β grains of the TMCs-Ⅰ and TMCs-Ⅱ were significantly refined. In addition, both equiaxed and lamellar α phase were formed in the TMCs-Ⅱ, in which various orientation relationships (ORs) between TiB and α phase occurred and the presence or absence of OR between TiB and β phase was responsible for the different morphologies of α phase. The yield strength of the DLDed TMCs-Ⅰ and TMCs-Ⅱ increased by 10.7 % and 38.8 % in comparison with that of the DLDed Ti6242, and both the load-bearing strengthening and fine-grain strengthening effects effectively enhanced the strength of the composites.
直接激光沉积(DLD)技术在制造形状复杂的钛基复合材料(TMC)部件方面具有巨大潜力。通过 DLD 技术,用预混合的 TiB2/Ti6242 粉末制造出了 TiB 晶须增强的 Ti6242 基复合材料。对混合均匀度和球磨 TiB2/Ti6242 粉末的变形率进行了定量表征,以选择最佳球磨参数。使用两种不同重量分数的 TiB2/Ti6242 粉末(2 wt%TiB2/Ti6242 和 5 wt%TiB2/Ti6242),以获得由于 DLD 过程中凝固路径的变化而导致复合材料中 TiB 晶须的不同分布。由 2 wt%TiB2/Ti6242 粉末制得的 TMCs-Ⅰ 中的 TiB 晶须在低共晶区凝固后呈现出不连续的网络结构,而由 5 wt%TiB2/Ti6242 粉末制得的 TMCs-Ⅱ 中的 TiB 晶须则由于在高共晶区凝固而随机分布。与 DLDed Ti6242 相比,TMCs-Ⅰ 和 TMCs-Ⅱ 的 α 晶粒和 β 晶粒明显细化。此外,TMCs-Ⅱ中还形成了等轴和片状α相,其中TiB和α相之间存在各种取向关系(OR),TiB和β相之间是否存在OR是造成α相形态不同的原因。与 DLDed Ti6242 相比,DLDed TMCs-Ⅰ 和 TMCs-Ⅱ 的屈服强度分别提高了 10.7% 和 38.8%,承载增强效应和细晶粒增强效应都有效地提高了复合材料的强度。