Novel Brazing Filler Metals using High Entropy Alloys

使用高熵合金的新型钎焊填充金属

• 批准号: EP/S032169/1
• 负责人: Russell Goodall
• 金额: $ 139.2万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FS032169%2F1
• 关键词: Novel; Brazing; Filler; Metals; using

Brazing is an important process for joining materials. It is quick and permits high strength, and is unique among high-temperature permanent joining methods in leaving the materials being joined largely unchanged; hence it can make complex joints and join dissimilar and difficult to weld materials (e.g. metals to ceramics and high Al/Ti content nickel superalloys respectively). It works by having a specific alloy, called a Brazing Filler Metal (BFM), introduced between the parts to be joined. Thermal treatment of the assembly is used to melt and solidify the BFM, forming a bond. These BFMs are designed specifically for different types of bonding situation, and can have many different compositions.Brazing is a key technology for many advanced applications, including the aerospace and nuclear sectors, but it has limitations. As the service requirements become more demanding, and base metals are refined, new BFMs must be developed. Some specific problems facing brazing technology today include:1) Widening the spectrum of materials that can be joined (including higher temperature materials, bonding metals to ceramics, and also lower process temperatures for materials that cannot survive those of existing brazing alloys; functional ceramics and high strength 7000 series aluminium alloys, for example), would open up a whole host of novel technologies, using both existing and advanced materials in new ways2) High temperature brazing uses additions such as boron or silicon to suppress the BFM melting point. They do this well, but also introduce brittle intermetallic phases in the joint region, limiting mechanical performance.3) In practice, the parameters for brazing are determined on an application-specific basis, by experimental trial and error. Greater fundamental understanding of the brazing process will render this more efficient, permitting the brazing conditions to be designed.This project builds the understanding to address such challenges.A new type of alloy, High Entropy Alloys (HEAs) has recently come to the fore for alloy design. In these alloys, similar amounts of many elements are combined, rather than the typical approach of main solvent element with small additions of other elements to adjust the properties. Some HEAs have reported properties desirable for BFMs; e.g. the ability to add large amounts of elements to control melting point or wetting and flow behaviour without inducing brittle phases, and the multicomponent nature could mediate the transition in a joint between dissimilar materials. However, the physical metallurgy of HEAs is still relatively poorly understood, and their use in brazing has only been explored to a very limited extent.In this work we are investigating systematically the design, understanding and use of HEAs as BFMs. This both adds to our fundamental understanding of this intriguing new class of alloys, and provides the knowledge and skills to permit the design of new products for industry. The data and computer models of the brazing process we will generate give the design methods and data for the development of brazing parameters, which is currently done on a case-by-case basis.The project brings together the UK academic and industrial community on brazing for the first time, and will act as a focus for brazing interest. Aided by our industrial partners we will demonstrate the outcome of this work by two example case studies of alloy development:I) Reduced cost BFM for aero engines; current alloys contain significant amounts of Au and so a noble metal-free BFM, with appropriate performance, would reduce costs.II) Fusion BFM; to build advanced fusion reactor designs, it is necessary to join tungsten blocks on the reactor interior to copper pipes for coolant. This is currently done with BFMs with melting points <325degC; this limits operating temperatures. A new BFM would improve the performance and give more design flexibility for fusion reactor components.

钎焊是连接材料的重要工艺。它是快速的，并允许高强度，并且在高温永久连接方法中是独特的，在很大程度上保持被连接的材料不变;因此，它可以制造复杂的接头，并连接不同的和难以焊接的材料（例如，分别将金属连接到陶瓷和高Al/Ti含量的镍高温合金）。它的工作原理是在要连接的部件之间引入一种称为钎焊填充金属（BFM）的特定合金。组件的热处理用于熔化和固化BFM，形成粘合。这些BFM是专为不同类型的连接情况而设计的，可以有许多不同的成分。钎焊是许多先进应用的关键技术，包括航空航天和核领域，但它有局限性。随着服务要求变得更加苛刻，以及贱金属的精炼，必须开发新的BFM。目前钎焊技术面临的一些具体问题包括：1）拓宽可连接材料的范围（包括高温材料，将金属结合到陶瓷，以及对于不能经受现有钎焊合金的材料的较低工艺温度;例如，功能陶瓷和高强度7000系列铝合金），将开辟一系列新技术，以新的方式使用现有的和先进的材料2）高温钎焊使用诸如硼或硅的添加物来抑制BFM熔点。它们在这方面做得很好，但也会在接头区域引入脆性金属间相，限制机械性能。3）在实践中，钎焊参数是根据具体应用，通过实验反复试验确定的。对钎焊工艺有更深入的了解将使其更有效，从而设计出钎焊条件。本项目建立了应对这些挑战的理解。一种新型合金--高熵合金（HEAs）最近在合金设计中脱颖而出。在这些合金中，相似量的许多元素组合在一起，而不是典型的主要溶剂元素与少量添加的其他元素来调节性能的方法。一些HEA报告了BFM所需的特性;例如，添加大量元素以控制熔点或润湿和流动行为而不诱导脆性相的能力，以及多组分性质可以调解不同材料之间的接头中的过渡。然而，HEAs的物理冶金学仍然是相对知之甚少，它们在钎焊中的使用只被探索到一个非常有限的程度。在这项工作中，我们正在系统地研究HEAs作为BFM的设计，理解和使用。这既增加了我们对这一有趣的新合金类别的基本理解，又提供了允许为工业设计新产品的知识和技能。我们将生成的钎焊过程的数据和计算机模型为钎焊参数的开发提供设计方法和数据，目前正在逐个案例地进行。该项目首次汇集了英国学术界和工业界的钎焊，并将成为钎焊兴趣的焦点。在我们的工业合作伙伴的帮助下，我们将通过两个合金开发的案例研究来展示这项工作的成果：I）降低航空发动机的BFM成本;目前的合金含有大量的Au，因此具有适当性能的无贵金属BFM将降低成本。II）聚变BFM;为了建造先进的聚变反应堆设计，有必要将反应堆内部的钨块连接到冷却剂铜管上。这目前是用熔点<325摄氏度的BFM完成的;这限制了操作温度。新的BFM将提高性能，并为聚变反应堆部件提供更多的设计灵活性。

项目成果

The performance of a brazing filler based on eutectic high entropy alloy designed by machine learning

机器学习设计的基于共晶高熵合金的钎料性能

• 发表时间: 2022
• 作者: Sanuy Morell X

An investigation into the shear strength of furnace brazed joints using additively manufactured surfaces

使用增材制造表面对炉钎焊接头的剪切强度进行研究

• 发表时间: 2022
• 作者: Livera F

High Entropy Alloys as Filler Metals for Joining.

• DOI: 10.3390/e23010078
• 发表时间: 2021-01-07
• 期刊: Entropy (Basel, Switzerland)
• 作者: Luo D;Xiao Y;Hardwick L;Snell R;Way M;Sanuy Morell X;Livera F;Ludford N;Panwisawas C;Dong H;Goodall R
• 通讯作者: Goodall R

On the origin of mosaicity in directionally solidified Ni-base superalloys

定向凝固镍基高温合金镶嵌性的起源

• DOI: 10.1016/j.actamat.2021.117180
• 发表时间: 2021
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: Strickland J

Development of a Novel Ni-Based Multi-principal Element Alloy Filler Metal, Using an Alternative Melting Point Depressant

• DOI: 10.1007/s11661-021-06246-0
• 发表时间: 2021-04
• 期刊: Metallurgical and Materials Transactions A
• 作者: L. Hardwick;Pat Rodgers;E. Pickering;R. Goodall