Nanostructures Integrated Laser Shock Peening (nLSP) Processes and Their Mechanisms for Enhanced Fatigue Performance

纳米结构集成激光冲击强化 (nLSP) 工艺及其增强疲劳性能的机制

• 批准号: 0900327
• 负责人: Gary Cheng
• 金额: $ 35万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0900327&HistoricalAwards=false
• 关键词: Nanostructures; Integrated; Laser; Shock; Peening

The research objective of this award is to investigate an innovative hybrid process combining laser shock peening with creation of nanostructures to minimize the relaxation of compressive residual stresses and work hardening. This project will discover the fundamental process mechanisms of the nanoparticle integrated laser shock peening process, and understand how this process produces the unique micro/nanostructures, which results in stabilized residual stresses and work hardening. Experiments and simulations will be conducted to investigate the effects of the type, size and distribution of the nanoparticles on the resulting microstructure and residual stress distribution. The stability of residual stress and dislocation structure under different temperatures and cyclic loadings will be studied using transmission electron microscopy and X-ray diffraction. Dislocation-pinning mechanisms will be investigated to explain the stabilizing effects. In order to study the mechanism of fatigue life enhancement, we will build a fatigue life model to predict the improved fatigue life considering the time variant residual stresses and hardness under real service conditions. Fatigue testing experiments will be designed to validate this model.The successful completion of this work will make an improvement to laser shock peening that produces compressive residual stress and a work hardening layer. This work can ensure the benefit of integrating a pre-stressing concept into component design with minimum risk for improved fatigue life, increased reliability and reduced weight. The impact can be transferred to the majority of load-carrying and structural components. This project will meet the challenges of education in materials science, engineering and manufacturing by (a) enhancing interdisciplinary and nontraditional manufacturing for research and education in Purdue University, (b) providing a multidisciplinary research opportunity for students to advance discovery and understanding of cutting edge manufacturing processes and (c) outreach to undergraduate and graduate students to retain them in science and engineering, especially underrepresented and minority students.

该奖项的研究目标是研究一种创新的混合工艺，将激光冲击强化与纳米结构的创建相结合，以最大限度地减少压缩残余应力和加工硬化的松弛。 该项目将发现纳米颗粒集成激光冲击强化工艺的基本工艺机制，并了解该工艺如何产生独特的微/纳米结构，从而实现稳定的残余应力和加工硬化。 将进行实验和模拟来研究纳米颗粒的类型、尺寸和分布对所得微观结构和残余应力分布的影响。 利用透射电子显微镜和X射线衍射研究不同温度和循环载荷下残余应力和位错结构的稳定性。 将研究位错钉扎机制以解释稳定效应。 为了研究疲劳寿命延长的机制，我们将建立一个疲劳寿命模型来预测考虑实际使用条件下随时间变化的残余应力和硬度的疲劳寿命的提高。 将设计疲劳测试实验来验证该模型。这项工作的成功完成将改进产生压缩残余应力和加工硬化层的激光冲击喷丸。 这项工作可以确保将预应力概念集成到部件设计中的好处，同时将提高疲劳寿命、提高可靠性和减轻重量的风险降至最低。冲击力可以转移到大多数承载部件和结构部件上。 该项目将通过以下方式应对材料科学、工程和制造教育的挑战：(a) 加强普渡大学的跨学科和非传统制造研究和教育，(b) 为学生提供多学科研究机会，以促进对尖端技术的发现和理解制造工艺；(c) 向本科生和研究生进行推广，以留住他们继续从事科学和工程领域的工作，特别是代表性不足的学生和少数族裔学生。