Design and Fabrication of Graded Materials with the Laser Engineered Net Shaping Process

采用激光工程净成形工艺设计和制造梯度材料

• 批准号: 0758622
• 负责人: John DuPont
• 金额: $ 29.5万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0758622&HistoricalAwards=false
• 关键词: Design; Fabrication; Graded; Materials; Laser

The objective of this research is to develop methods for designing and fabricating graded transition joints for avoiding failures in dissimilar welds. The graded transition joints will consist of gradual and controlled changes in composition and resultant properties. This will significantly reduce or eliminate failures in dissimilar welds that are currently caused by very sharp changes in composition and properties. The optimal gradation in properties will first be determined using structural optimization routines. This information will then be utilized to fabricate various graded transition joints using microstructural modeling and the Laser Engineered Net Shaping (LENS) process. The performance of these joints will be evaluated relative to the industry standard joints using a variety of techniques, including light/electron microscopy, microhardness testing, high temperature tensile testing, and creep-rupture analysis. Optimal graded joints will then be installed into the power plants of the industrial partner along with conventional joints for side-by-side field testing.The need to join dissimilar materials is expected to increase as more demand is placed on the performance of materials under conditions of increasing stress, temperature, and corrosive environment. Graded materials offer significant potential for joining dissimilar materials, but methods for designing these joints for improved performance are not yet available. In addition, dissimilar weld failures currently carry significant economic impact. For example, a single dissimilar weld failure can cost an electric power company up to $850,000/day in down time and lost revenue. If successful, the results of this research will lead to development of methods for optimizing the design, fabrication, and performance of graded materials that can be used in a variety of applications. The results will also lead to an improved understanding of the complex relationships between processing, structure, and properties in LENS processing. Lastly, the direct implementation of the technology for joining dissimilar materials in power generation applications will provide significant cost savings by eliminating dissimilar weld failures.

这项研究的目的是开发设计和制造分级过渡接头的方法，以避免焊缝中的故障。 分级过渡接头将包括组成和结果性质的逐渐变化和受控的变化。这将大大减少或消除不同焊缝的故障，而这些焊缝目前由组成和特性发生急剧变化引起的失败。属性的最佳级别将首先使用结构优化例程确定。然后，该信息将用于使用微结构建模和激光工程净成型（镜头）工艺来制造各种分级过渡接头。这些关节的性能将使用各种技术进行评估，包括光/电子显微镜，微硬度测试，高温拉伸测试和蠕变破裂分析。然后，最佳分级接头将安装到工业合作伙伴的发电厂，以及用于并排现场测试的常规关节。随着在压力，温度增加和腐蚀性环境的情况下，预计相差材料的需求有望增加。分级材料为加入不同的材料提供了巨大的潜力，但是尚无设计这些关节以提高性能的方法。此外，不同的焊缝故障目前会产生重大的经济影响。例如，单个不同的焊接故障可能会使一家电力公司在停机时间内每天高达85万美元，而收入损失。如果成功，这项研究的结果将导致开发用于优化可用于各种应用中的分级材料的设计，制造和性能的方法。结果还将导致人们对镜头处理中的处理，结构和属性之间的复杂关系的增强理解。最后，在发电应用中加入不同材料的技术的直接实施将通过消除不同的焊接故障来节省大量成本。