The influence of laser parameters, scanning strategies and material on the fatigue strength of a stochastic porous structure
The influence of laser parameters, scanning strategies and material on the fatigue strength of a stochastic porous structure
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DOI：
10.1016/j.addma.2018.05.024
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发表时间：
2018-08-01
影响因子：
11
通讯作者：
Jeffers, Jonathan R. T.
中科院分区：
文献类型：
--
作者：
Ghouse, Shaaz;Babu, Sarat;Jeffers, Jonathan R. T.
增材制造（AM）多孔材料在疲劳方面的定性和定量表现都不同于块状材料，通常用于连续块状材料疲劳设计的关系不适用于增材制造多孔材料，特别是低刚度应用。本研究探讨了粉末床熔合过程中使用的制造方法和材料如何影响给定刚度的随机多孔材料的抗压强度和高周疲劳强度。使用不同的激光参数、3种扫描策略（轮廓、点、脉冲）和4种材料制作样品。所研究的材料是两种钛合金：商业纯2级（CP-Ti）和Ti6Al4V ELI，商业纯钽（Ta）和钛钽合金（Ti-30Ta）。在单片金属的疲劳测试和固体和多孔AM材料的静态疲劳测试中观察到的趋势并不总是表明多孔AM材料的高周疲劳行为。与固体材料不同，多孔钽和钛钽合金在给定刚度下具有最大的疲劳强度，比CP-Ti高8%，比Ti6Al4V ELI高19%。激光参数和扫描策略的优化也使多孔AM材料在给定刚度下的疲劳强度提高了7-8%。
Additive manufactured (AM) porous materials behave quantitatively and qualitatively differently in fatigue than bulk materials, and the relationships normally used for the fatigue design of continuous bulk materials are not applicable to AM porous materials particularly for low stiffness applications.This study investigated how the manufacturing methods and the material used during powder bed fusion affects the compressive strength and high cycle fatigue strength of a stochastic porous material for a given stiffness. Specimens were manufactured using varying laser parameters, 3 scan strategies (Contour, Points, Pulsing) and 4 materials. The materials investigated were two titanium alloys: commercially pure grade 2 (CP-Ti) and Ti6Al4V ELI, commercially pure tantalum (Ta) and a titanium-tantalum alloy (Ti-30Ta).The trends observed during fatigue testing for monolithic metals and statically for solid and porous AM materials were not always indicative of the high cycle fatigue behaviour of porous AM materials. Unlike their solid counterparts, porous tantalum and the titanium-tantalum alloy had the greatest fatigue strength for a given stiffness, 8% greater than CP-Ti and 19% greater than Ti6Al4V ELI. Optimisation of the laser parameters and scan strategies was found to also increase the fatigue strength for a given stiffness of porous AM materials by 7-8%.