Microstructural Impact on the Machinability of Titanium Alloys

微观结构对钛合金切削加工性的影响

基本信息

批准号：
1727525
负责人：
Patrick Kwon
金额：
$ 59.98万
依托单位：
Michigan State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-15 至 2021-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1727525&HistoricalAwards=false
关键词：
Microstructural Impact Machinability Titanium Alloys

项目摘要

Titanium alloys have an excellent combination of light weight and high strength, and thus are desirable for a number of engineering applications. Before final production, most titanium parts must undergo a machining process, which is often difficult and costly. Damage to both the titanium part and the machine tool are common, and little is known about what leads to this damage or how it can be controlled. This award supports fundamental research to investigate the mechanisms of deformation and wear during the process of machining titanium alloy parts. The very fine-scale structure of the alloys holds important keys to identify the root causes of tool wear, cutting behavior, and segmented chips in titanium machining, and understanding the fundamental relationships between this structure and processing will allow researchers to build the knowledge needed to to identify cutting tool design strategies and to optimize the alloy structure for better machinability, and predict the performance of a component. This new knowledge will have broad applicability in a number of manufacturing industries, including aerospace, automotive, and infrastructure. Additionally, strong educational benefits will result from this award, including diverse opportunities and experience for students in state-of-the-art research programs.This interdisciplinary team will bring researchers from Mechanical Engineering and Materials Science together to develop a fundamental understanding of how differences in the microstructure of titanium alloys affect machinability metrics. The microstructure of titanium alloys is quite complex, and most alloys (including the most common commercially used alloy, Ti-6Al-4V) have two distinct phases: an anisotropic hexagonal close-packed (HCP) phase, and a more isotropic body-centered cubic (BCC) phase. As a result of prior forming and heat treatment processes, many combinations of the two phases in various morphologies and textures are possible. This work will investigate how the microstructure prior to machining affects machinability metrics such as chip segmentation, tool wear, process dynamics, and the surface integrity of a finished product. The objective of this work is to identify and quantify the interplay between the titanium microstructure and these machinability metrics. A successful outcome will lead to science-based insights and rationale for choices of tools and cutting parameters that are tuned to the microstructure and composition of an alloy, and result in machined components with high structural integrity. This new knowledge will lead to the ability to describe and anticipate many observed phenomena such as micro-chipping on cutting tools, segmented chips and excessive tool wear at high cutting speeds. This will lead to rational approaches to reduce the overall processing cost by optimizing material specifications for machinability and product performance, as well as identifying improved ways to machine titanium alloys.

钛合金具有轻质和高强度的优异结合，因此适合许多工程应用。在最终生产之前，大多数钛零件必须经过机械加工过程，这通常是困难且成本高昂的。钛零件和机床的损坏很常见，但人们对导致这种损坏的原因或如何控制这种损坏知之甚少。该奖项支持研究钛合金零件加工过程中变形和磨损机制的基础研究。合金的非常精细的结构对于确定钛加工中刀具磨损、切削行为和分段切屑的根本原因具有重要的关键作用，并且了解这种结构和加工之间的基本关系将使研究人员能够建立所需的知识确定切削刀具设计策略并优化合金结构以获得更好的机械加工性，并预测部件的性能。这些新知识将在许多制造业中具有广泛的适用性，包括航空航天、汽车和基础设施。此外，该奖项还将带来巨大的教育效益，包括为学生提供最先进研究项目的多种机会和经验。这个跨学科团队将把来自机械工程和材料科学的研究人员聚集在一起，对差异如何产生基本理解钛合金的微观结构影响切削加工性指标。钛合金的微观结构相当复杂，大多数合金（包括最常见的商用合金 Ti-6Al-4V）都有两个不同的相：各向异性六方密排 (HCP) 相和更具各向同性的体心相立方（BCC）相。由于先前的成型和热处理工艺，不同形态和纹理的两相的多种组合是可能的。这项工作将研究加工前的微观结构如何影响切削加工指标，例如切屑分割、刀具磨损、工艺动态和成品的表面完整性。这项工作的目的是确定和量化钛微观结构与这些可加工性指标之间的相互作用。成功的结果将带来基于科学的见解和理由，以选择适合合金微观结构和成分的刀具和切削参数，并产生具有高结构完整性的加工部件。这些新知识将导致能够描述和预测许多观察到的现象，例如切削刀具上的微崩刃、分段切屑以及高切削速度下的刀具过度磨损。这将导致通过优化可加工性和产品性能的材料规格以及确定加工钛合金的改进方法来降低总体加工成本的合理方法。