关键词： 镁合金WE43   微观结构演变   孪晶   织构   动态再结晶  

摘要： 0引言工业高速发展随之带来的环境污染和资源紧张问题日益突出,因此大力研发绿色工程材料势在必行。被誉为“21世纪绿色工程材料”[1-2]的镁合金由于其优异的铸造、切削加工特性以及易回收再利用等特点,在绿色制造方面表现出巨大的潜力。其中WE43稀土镁合金更是凭借高比强度、优异的抗蠕变性以及良好的耐蚀性等,成为广泛应用于航空航天和交通运输行业的商用镁合金之一[3-6]。作为最轻的金属材料,镁合金在航空运输的广泛应用将为节能减排带来巨大的效益,然而镁合金相对强度较低,很少作为承重构件应用于航空领域;并且室温成形性差,进一步限制了其应用。

关键词： X射线光电子能谱   抗菌   抗腐蚀   生物相容性  

摘要： 牙缺失是口腔临床中发病率极高的疾病之一。种植修复已成为当前修复缺失牙的常规治疗方案,常用种植材料是钛及钛合金材料,其具有无毒、弹性模量与人体硬组织相匹配和种植修复成功率高等优点,但钛基种植体生物活性差,甚至会出现失效的情况。因此,通过对齿科材料进行表面改性,可以提高植入物表面的抗菌性、耐腐蚀性并加快骨结合的过程,从而提高其成功率,有利于其长期存活。X射线光电子能谱(XPS)在对改性材料表面机理进行分析方面具有“高灵敏”和“超微量”等独特优势,在新型齿科医用材料的研究中,XPS技术可用于分析材料的表面成分和化学状态,这对研究材料的抗菌性、耐腐蚀性和生物相容性等关键性能至关重要。通过XPS技术,可以准确地了解材料表面的元素组成、化学价态以及表面化学状态等信息,从而评估材料的生物安全性和功能性。

关键词： CdTe/CdS/SiO_(2)量子点   毒性   分布   蓄积   生物相容性  

摘要： CdTe/CdS/SiO_(2)量子点因其明亮的发光特性和优异的光稳定性而在生物领域具有很大的应用潜力,但其生物安全问题仍不清楚。该研究通过低剂量(0.4 mg/kg)和高剂量(4 mg/kg)的单次腹腔注射来评估CdTe/CdS/SiO_(2)量子点对小鼠的亚急性毒性,同时监测42 d的体重、脏器系数、血细胞计数、氧化指数、组织病理学变化和生物分布。结果表明,注射CdTe/CdS/SiO_(2)量子点后,小鼠体重和脏器系数无显著差异。荧光观察显示,CdTe/CdS/SiO_(2)量子点在器官中的早期积累为肺>脾>肝>肾>心,在分布上表现出明显的偏好。电感耦合等离子体质谱分析显示,CdTe/CdS/SiO_(2)量子点注射后在小鼠主要器官积累42 d,且早中期主要分布在脾和肺,后期主要分布在肝和肾。量子点处理组与对照组间的大部分血细胞计数和氧化指数均无显著性差异。此外,与对照组相比,经CdTe/CdS/SiO_(2)量子点处理的小鼠未发现明显的组织病理学异常。简而言之,CdTe/CdS/SiO_(2)量子点在小鼠体内体现出了良好的生物相容性,这些发现为量子点的安全应用提供了有价值的数据。

关键词： 天然聚合物   生物相容性   水凝胶   设计原则  

摘要： 天然聚合物水凝胶是一种绿色智能材料,因具有生物相容性好、原材料易得、成本低廉以及在生物医学、组织工程、柔性穿戴设备等领域的应用潜力而备受关注。尽管天然聚合物水凝胶已经被大量的研究,但仍需要一项可以使用不同材料和制作方法来进行水凝胶设计的原则。为了增强天然聚合物水凝胶的性能以适应不同的工作条件,介绍了壳聚糖、海藻酸盐和透明质酸这3种常用天然聚合物水凝胶的设计原则及其应用情况。

关键词： deformed magnesium alloy   bimodal structure   deformation behavior   DRX mechanism   synergistic enhancement of strength and plasticity   deformed magnesium alloy   bimodal structure   deformation behavior   DRX mechanism   synergistic enhancement of strength and plasticity  

摘要： The magnesium alloy exhibits a notable plasticity limitation due to its hcp structure. In recent years, the development of a bimodal structure, consisting of deformed coarse grains and recrystallized fine grains, has emerged as an effective strategy to balance the strength and plasticity of magnesium alloys, offering a new avenue for property. This optimization study investigates the formation mechanism and deformation behavior of the bimodal structure in AZ31 magnesium alloy by controlling the extrusion process. The formation of the bimodal structure is attributed to the incomplete dynamic recrystallization during plastic deformation and the particle-stimulated nucleation effect of the secondary phase. During deformation, fine grains endure higher stresses, while coarse grains accommodate more strain. The fine grains significantly contribute to the improved strength of the AZ31 magnesium alloy, while the coordinated deformation of the coarse grains ensures excellent plasticity. Leveraging the superior deformation capability of the bimodal structure, fine-grained AZ31 magnesium alloy was successfully fabricated through further extrusion, achieving outstanding mechanical properties: a tensile strength of 265 MPa, a yield strength of 112 MPa, and an elongation of 19%. This demonstrates the synergistic enhancement of strength and plasticity.

关键词： magnesium alloy   ultrahigh-pressure   strength-ductility synergy   corrosion resistance   hydrogen storage property  

摘要： Magnesium alloys are the lightest metallic structural materials. The density of magnesium alloys is similar to 1.7 g/cm(3), which is similar to 2/3 of the aluminum alloy, similar to 2/5 of titanium alloys, and similar to 1/4 of steel. Magnesium alloys possess high specific strength, excellent casting performance, excellent biocompatibility, good electromagnetic shielding performance, remarkable damping performance, and ease of recovery. They have broad application potential in aerospace, defense, automobile transportation, biomedical, electronic 3C, construction, and energy fields. China has substantial Mg resources. The development of low-cost and high-performance magnesium alloys in the lightweight field can transform resource advantages into industrial benefits while promoting energy conservation and emission reduction in production and daily life. This is strategically significant for the enhancement of the country's technology industry and the achievement of the objectives of "carbon peak and carbon neutrality". However, commercial magnesium alloys currently possess relatively low strength, poor ductility, and corrosion resistance compared with common metallic structural materials like steel and aluminum alloys, significantly hindering the large-scale industrial application of magnesium alloys as structural materials. Many methods exist to enhance the comprehensive mechanical properties of magnesium alloys. Conventionally, the microstructure of magnesium alloys can be modified by adding alloying elements, plastic deformation, and heat treatment. The strength of magnesium alloys can be improved through grain refinement, work hardening, solid solution strengthening, and precipitation strengthening. Nevertheless, magnesium alloys prepared through these traditional methods can achieve excellent strength but at the expense of ductility, leading to the strength- ductility tradeoff in the magnesium alloy. At present, ultrahigh-pressure (UHF) treatment technology can a

关键词： magnesium alloy   gigacasting process   defect   microstructure   process  

摘要： The demand for lightweighting is rapidly increasing to meet the carbon peak and neutrality goals. Gigacasting integrates stamping and welding processes into a single high-pressure die-casting operation, streamlining production workflows and considerably enhancing production efficiency, thereby accelerating advancements in automotive lightweighting. Magnesium alloys, which are the lightest metallic structural materials at present, are superior choices for lightweighting because of their low density, high strength, and excellent casting performance. Magnesium alloy gigacasting has enormous potential for automotive applications, enabling the production of lightweight automotive components with superior mechanical properties. However, this process faces challenges because magnesium alloys' active chemical properties and high susceptibility to hot tearing, combined with their large size, thin wall thickness, and complex geometries, make defects like porosity and hot tearing prevalent. These defects greatly impair the performance of gigacast components. Preventing and mitigating casting defects is critical for improving the yield and quality stability of magnesium alloy gigacastings, thereby facilitating their wide spread application in industries like automotive and aerospace. To address these issues, the causes and control measures for three common defects (porosities, defect bands, and hot tearing) are briefly explored in this study. Progress and challenges in defect control, focusing on melt treatment, alloy development, process optimization, and structural design, are also outlined. This review aims to provide valuable insights into defect control strategies for developing high-performance magnesium alloy gigacastings.

摘要： 因镁合金具有良好的弹性模量、可降解和促进骨修复等性能成为了骨科内植物材料的研究热点。目前，大多数生物镁合金因降解过快不能满足骨科需求，稀土镁合金具有良好的耐腐蚀性等性能，有望成为临床骨科内植物的重要材料。本文就稀土的生理作用、对镁合金性能的影响，稀土镁合金体外生物相容性、动物体内生物相容性、对腱骨愈合的影响及临床骨科应用现状等研究进展进行综述。 Due to their good properties of elastic modulus, degradability and ability to promote bone repair, magnesium alloys have become a research hotspot in research of orthopedic implants. Nevertheless, most of the biomedical magnesium alloys currently available fail to meet the requirements in orthopedics because of their rapid degradation after implantation. Rare earth-magnesium alloys possess excellent corrosion resistance and are expected to become important materials as clinical orthopedic implants. This review summarizes the recent progress in studies of the physiological functions of rare earth elements, the effects of supplementation of rare earth elements on biomechanical properties and the in vitro and in vivo biocompatibility of magnesium alloys, and their contribution to tendon-bone healing, addressing also the current clinical orthopedic applications of different rare earth-magnesium alloys, challenges, and future strategies for improving these alloys.

关键词： 镁合金   激光焊接   重建网络   无监督   焊缝缺陷  

摘要： 针对镁合金激光焊接焊缝表面缺陷形态复杂、特征不明显，以及传统无监督检测方法漏检、误检率高等问题，提出了一种基于改进重建网络的无监督缺陷检测方法。通过在网络的编码器开端、网络层之间、及全连接层中，分别引入ASPP、CBAM、SSPCAB模块，以及在编码器与解码器之间添加所提出的多尺度特征融合模块MSFFM，提高网络特征提取与异常目标定位能力，增强缺陷位置的重建精度与相邻网络层间的特征信息融合。在自建的镁合金激光焊接焊缝数据集与MVTec AD公共数据集上进行了有效性与通用性的实验验证。实验结果表明，该方法可对镁合金焊缝表面的小样本复杂形态缺陷进行有效识别、精准分割与定位，且具备良好的通用性。