Surface improvement of laser clad Ti-6Al-4V using plain waterjet and pulsed electron beam irradiation
Surface improvement of laser clad Ti-6Al-4V using plain waterjet and pulsed electron beam irradiation
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DOI：
10.1016/j.jmatprotec.2014.11.035
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发表时间：
2015-04-01
影响因子：
6.3
通讯作者：
Clare, A. T.
中科院分区：
文献类型：
--
作者：
Farayibi, P. K.;Abioye, T. E.;Clare, A. T.
激光熔覆是一种灵活的工艺，可用于提高部件的使用寿命并在磨损时进行修复。这在部件价值很高，因此更换成本很高的情况下尤其重要。迄今为止，通过激光熔覆可实现的表面光洁度很差，并且其特征在于对应于与该工艺相关的单个珠的脊。激光熔覆正越来越多地应用于难以通过常规磨削程序处理的共形表面，常规磨削程序也可能由于不连续的熔覆区域而无效。因此，需要一种能够将特定表面光洁度引入复杂部件的自由形式方法。因此，在这项研究中，一个过程链，将平原水射流（PWJ），然后用脉冲电子束照射的激光熔覆表面的Ti-6Al-4V的表面改性。最初表面的特点是大凹陷的峰谷高度为200 +/- 18 μ m和波纹度为49 μ m。在采用345 MPa的水头压力以90度角冲击包覆表面、250 mm/min的射流横向速度、3 mm的间隔距离和0.25 mm的研磨重叠2遍的加工时，可以通过研磨到480 +/-10 μ m的深度来消除峰-谷轮廓。获得了以14.9 μ m的表面波纹度、12.6 μ m Ra和44 μ m平直度为特征的平坦表面。PWJ铣削表面的特点是深腔，阶梯状断裂表面，裂纹和次表面隧道，然而，与脉冲电子束照射的应用程序，这些表面特征中的大部分被消除与6.2 μ m Ra光洁度产生的相对光滑的表面。(C)2014作者由爱思唯尔公司出版
Laser cladding is a flexible process which can be used to enhance the lifetime of components and repair them when worn. This is especially relevant where components are highly valued, and therefore costly to replace. To date, the surface finish achievable by laser cladding is poor and is characterised by ridges which correspond to the individual beads associated with the process. Increasingly laser cladding is being applied to conformal surfaces which are difficult to process by conventional grinding procedures which may also be ineffective because of discontinuous clad regions. There is therefore a need for a freeform approach which is capable of introducing specific surface finishes to complex components. Hence, in this study, a process chain incorporating plain water jet (PWJ) followed by a pulsed electron beam irradiation was used for the surface modification of laser clad surfaces of Ti-6Al-4V. Initially the surface was characterised by large recesses with peak-trough heights of 200 +/- 18 mu m and waviness of 49 mu m. Upon processing employing water head pressure of 345 MPa impinging the clad surface at an angle 90 degrees, 250 mm/min jet traverse speed, 3 mm stand-off distance and 0.25 mm milling overlap with 2 passes, it was possible to eliminate the peak-trough profile by milling to a depth of 480 +/- 10 mu m. A flat surface characterised by a surface waviness of 14.9 mu m, 12.6 mu m Ra and 44 mu m straightness was achieved. PWJ milled surfaces were characterised by deep cavities, stepped fractured surfaces, cracks and sub-surface tunnels, however, with application of pulsed electron beam irradiation, most of these surface features were eliminated with a relatively smooth surface produced with 6.2 mu m Ra finish. (C) 2014 The Authors. Published by Elsevier B.V.