Optimum laser surface treatment of fatigue damaged Ti-6Al-4V alloy
Optimum laser surface treatment of fatigue damaged Ti-6Al-4V alloy
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DOI：
10.1016/s0921-5093(00)01360-5
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发表时间：
2001-04-15
期刊：
影响因子：
6.4
通讯作者：
Konstantino, E
中科院分区：
文献类型：
--
作者：
Altus, E;Konstantino, E
采用1.8 kW连续CO2激光器对钛6Al-4V合金进行了激光表面处理（LST），以提高其疲劳性能。该研究的目的是找到最佳的处理条件，这将延长材料的抗疲劳破坏能力，并探讨所涉及的机制。在疲劳寿命的不同阶段，将LST应用于循环加载的“三点弯曲”试样（R = 0.1，0.8 sigma（y）近表面应力）。利用红外热像仪测量了表面温度场。确定了两种基本机制，一种是与愈合机制（HM），它“擦除”先前的疲劳损伤达到一定水平，另一种是连接到微观组织机制（MM）。愈合被发现是有效的表面温度高于400 degreesC。在大多数情况下，除了温度低于600摄氏度和特定的激光条件下，微观结构的变化对耐疲劳性有负面影响。这两种机制的组合导致最佳LST为2 s和0.85 kW cm（-2），发现除了完全愈合外，疲劳寿命增加50%是由于MM。硬度和疲劳寿命之间也存在正相关关系。（C）2001 Elsevier Science B. V.版权所有。
A laser surface treatment (LST), which enhances fatigue resistance of Titanium 6Al-4V alloy has been studied by 1.8 kW CW-CO2 Laser. The aim of the study is to find optimal conditions of treatment, which will extend the material resistance to fatigue failure, and explore the mechanisms involved. The LST was applied to 'three point bend' specimens loaded cyclically (R = 0.1, 0.8 sigma (y) near surface stresses), at different stages of fatigue life. Temperature surface fields were found by infrared camera. Two basic mechanisms were identified, one is related to healing mechanism (HM), which 'erases' prior fatigue damage up to a certain level, and the other is connected to microstructure mechanism (MM). Healing was found to be effective for surface temperatures above 400 degreesC. In most cases, microstructure changes had a negative effect on fatigue resistance except for temperatures lower than 600 degreesC and specific laser conditions. The combination of both mechanisms lead to optimal LST of 2 s and 0.85 kW cm(-2), for which a 50% increase in fatigue life was found to be due to MM, in addition to a full healing. A positive correlation between hardness and fatigue life was also found. (C) 2001 Elsevier Science B.V. All rights reserved.