Microstructural and micromechanical assessment of aged ultra-fast sintered functionally graded iron/tungsten composites
Microstructural and micromechanical assessment of aged ultra-fast sintered functionally graded iron/tungsten composites
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DOI：
10.1016/j.matdes.2020.108652
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发表时间：
2020-06
影响因子：
8.4
通讯作者：
S. Heuer;B. Li;David J Armstrong;Y. Zayachuk;C. Linsmeier
中科院分区：
文献类型：
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作者：
S. Heuer;B. Li;David J Armstrong;Y. Zayachuk;C. Linsmeier
功能梯度（FG）铁/钨（Fe/W）复合材料被认为是在未来的聚变反应堆所需的钨钢接头的应力释放中间层。这两种材料的宏观分级允许热致应力的松弛，从而延长循环加载的异种材料接头的寿命。虽然许多性能，如热膨胀和强度，所制造的Fe/W复合材料是有前途的预期应用方面，温度引起的微观结构的变化及其对材料性能的影响仍然在很大程度上未被探索。考虑到Fesingle键W的热力学系统包含两种类型的金属间相，理解FG Fe/W复合材料的微观结构变化对于聚变反应堆的长期运行至关重要。采用扫描电镜（SEM）和X射线衍射（XRD）研究了含50和75vol%钨的超快速烧结Fe/W复合材料的显微组织。制造和热老化条件（300、500和800 °C，长达72小时）。通过纳米压痕测量所选复合材料的硬度和模量，并通过缺口微悬臂梁弯曲试验测试Fesingle bondW界面的断裂韧性。从微观结构和微观力学分析的结果进行了讨论，并评估材料的应用在聚变反应堆的基础上的微观结构与性能的关系。
Functionally graded (FG) iron/tungsten (Fe/W) composites are considered for stress-relieving interlayers in tungsten-steel joints, required in future fusion reactors. The macroscopic gradation of the two materials allows relaxation of thermally-induced stresses and hence extend the lifetime of the cyclic-loaded dissimilar materials joints. While many properties, e.g. thermal expansion and strength, of the as-manufactured Fe/W composites are promising with respect to the anticipated application, the temperature-induced microstructural changes and their effect on the material properties remain largely unexplored. Given that the thermodynamic system of Fesingle bondW contains two types of intermetallic phases, understanding the microstructural changes in the FG Fe/W composites is crucial for long-term operation of fusion reactors.In the present work, the microstructure of ultra-fast sintered Fe/W composites containing 50 and 75 vol% tungsten is studied via electron microscopy (SEM) and X-ray diffraction (XRD) in as-manufactured and thermal aged conditions (300, 500, and 800 °C for up to 72 h). The hardness and modulus of selected composites are measured via nanoindentation, and the fracture toughness of the Fesingle bondW interfaces is tested via notched micro-cantilever bending tests. The results from microstructural and micromechanical analyses are discussed, and the materials are evaluated for their application in fusion reactors based on the microstructure-to-property relationship.