摘 要

钨（W）以其高熔点、低溅射率、低蒸汽压、高热导率和低氚滞留量等的优点，成为聚变反应堆中最具应用前景的面对等离子体材料（PFMs）候选材料之一。在聚变反应堆的工况下，PFMs需要耐受瞬态高温、高热负荷、中子辐照、等离子体冲刷等苛刻的工作环境。

目前，面向等离子体钨基材料的研究，已从纯钨、二元合金向更为复杂的多元复合材料发展。本论文中，从聚变堆具体工况和材料结构角度，沿用L.Veleva等撰写的相关论文综合分析当前纯W、W-Y合金、及W-Y₂O₃复合材料为主要对象的材料性能和制备工艺。

在纯W中加入Y元素并充分混合后，由于Y的活性较高，使得纯W中的O元素与之结合成为细小的Y₂O₃颗粒，这种弥散分布的细小的第二相颗粒能有效的积累位错，从而改变W的性能，有效提高其硬度、密度和强度。而在纯W中直接加入Y₂O₃时，虽然强化效果较直接加入Y更为显著，但并不能改变W中的杂质元素分布，对材料密度的提高作用与直接加入Y较小，当杂质含量较高时材料的脆性反而会显著增加。

尽管加入Y和Y₂O₃能有效提高W材料的硬度、强度、密度等性能，但韧脆转变温度（DBTT）和脆性却也有所提高。所以工艺流程需要加以改善，如在制备原料过程中减少W中杂质的混入，杂质元素在晶界处偏聚会削弱晶界的强度，减少杂质能有效改善材料的韧性；制备超细晶钨基材料作为原料，细晶材料在拉伸过程中形变较为均匀，有效减少应力集中造成的开裂，使材料的韧性更好地表现出来。

本文的特色在于归纳总结了多种制备方法制备同种W基材料之间的差异，比较不同制备方法对材料性能的影响，并试图弄清金属及其氧化物在材料中所起到的作用，为更好地设计钨基材料提供帮助。

关键词：钨；面向等离子体材料；钇；材料性能

Abstract

Tungsten (W) with its high melting point, low sputtering rate and low tritium retention is one of the candidate materials for PFMs. Under the condition of convergent reactor, PFMs should be able to withstand the harsh working environment of high temperature, high thermal load, neutron irradiation, plasma scouring, and low tritium retention and permeability.

At present, the research of plasma-oriented tungsten-based materials has developed from pure tungsten and binary alloy to more complex composite materials. In this paper, from the specific working conditions and material structure of the reactor, the material properties and preparation process of the current pure W, w-y alloy and w-y₂o₃ composite materials are comprehensively analyzed using the relevant papers written by l. V eleva et al.

After Y elements are added into pure W and fully mixed, due to the high activity of Y, O elements in pure W are combined with it into tiny Y₂O₃ particles. Such dispersing tiny second-phase particles can effectively accumulate dislocation, thus changing the performance of W and effectively improving its hardness, density and strength. However, when Y₂O₃ is directly added to pure W, although the strengthening effect is more significant than that when Y is directly added, the distribution of impurity elements in W cannot be changed. The effect on the improvement of material density is less than that when Y is directly added to pure W. On the contrary, the brittleness of the material will increase significantly when the impurity content is high.

Although the addition of Y and Y₂O₃ can effectively improve the hardness, strength, density and other properties of W material, DBTT and brittleness are also improved. Therefore, the technological process needs to be improved. For example, in the process of preparing raw materials, the mixing of impurities in W is reduced. Impurity elements tend to gather at the grain boundary to weaken the strength of the grain boundary, and the toughness of the material can be effectively improved by reducing impurities. The ultrafine tungsten-based material was prepared as the raw material. The deformation of the ultrafine material was relatively uniform during the tensile process, which effectively reduced the cracking caused by stress concentration and made the toughness of the material better.

The characteristics of this paper are to summarize the differences between different preparation methods for the same W base materials, compare the effects of different preparation methods on the properties of materials, and try to understand the role of metals and their oxides in materials, so as to provide help for the better design of W base materials.

Keywords: tungsten; Plasma-orientedmaterials; Yttrium; Materialperformance

目录

摘要 1

Abstract 2

第1章 绪论 1

1.1课题研究意义及内容 1

1.2面向等离子体钨基材料研究现状 2

1.2.1新型钨基材料的研究现状 2

第2章 面向等离子体钨基材料的制备工艺概述 4

2.1粉末冶金法 4

2.2热等静压烧结法 4

2.3液相烧结法 5

2.4机械合金化 5

2.5其他制备方法 6

第3章 W、W-Y合金、及W-Y₂O₃复合材料 7

3.1钇元素 7

3.2不同制备方法下Y和Y₂O₃的材料性能 7

第4章 结论与展望 16

4.1结论 16

4.2展望 17

参考文献 18

致谢 20

附录1 21

附录2 22

第1章 绪论

1.1课题研究意义及内容

能源、信息及材料是现代化社会发展的三大支柱，而能源的发展则是其中的基础。能源发展程度从侧面上体现着一个国家的发展程度——越发达的国家，对能源的需求则越大。目前最经济的能源是²³⁵U或²³⁹Pu的裂变释放的能量，作为不可再生的清洁能源，存在两个不可避免的缺点，一是辐射安全问题，二是核废料的处理。而下一代的新能源，核聚变比核裂变更为优秀，不仅更加经济廉价，而且基本没有辐射及核废料的问题^[1]。

在核聚变反应中，因反应温度极高，在目前已知的所有材料中都无法承受其高温，且反应过程中释放的高能中子对材料产生的体损伤和高能离子产生的表面损伤是对材料的提出的更高要求。因此，聚变堆材料问题是排在等离子体控制之后的第二个研究课题。

面向等离子体作为直面聚变反应堆核心的第一道“防线”，其材料必须要具有良好的导热率、优良的抗热冲击性、较低的放射性、溅射产额及较高的熔点等材料性能^[2]。