Fiber laser induced surface modification/manipulation of an ultrasonically consolidated metal matrix

Abstract

Ultrasonic Consolidation (UC) is a manufacturing technique based on the ultrasonic joining of a sequence of metal foils. It has been shown to be a suitable method for fiber embedment into metal matrices. However, integration of high volume fractions of fibers requires a method for accurate positioning and secure placement to maintain fiber layouts within the matrices. This paper investigates the use of a fiber laser for microchannel creation in UC samples to allow such fiber layout patterns. A secondary goal, to possibly reduce plastic flow requirements in future embedding processes, is addressed by manipulating the melt generated by the laser to form a shoulder on either side of the channel. The authors studied the influence of laser power, traverse speed and assist gas pressure on the channel formation in aluminium alloy UC samples. It was found that multiple laser passes allowed accurate melt distribution and channel geometry in the micrometre range. An assist gas ai ded the manipulation of the melted material

Laser-Machined Microchannel Effect on Microstructure and Oxide Formation of an Ultrasonically Processed Aluminum Alloy

“…As detailed in Table 3, a higher gas pressure of 0.8 MPa decreased the width of the HAZ. It was suggested that a difference in surface tension between the channel boundaries and the center of the melt pool hindered a uni form distribution of the melt to both sides of the channel which has been discussed elsewhere [35]. Both, a higher gas pressure and a faster traverse speed, allow for less heat to be conducted into the material.…”

“…A Fiber laser allowed focusing the beam to narrow spot sizes which was necessary to achieve the desired channel width of 120/rm-150jtnn which was determined by the diameters of the intended future embedded fibers. A detailed analysis of the varied parameters on the channel/shoulder geometry has been shown elsewhere [35]. The beam quality factor of the fiber laser was M2 < 1.2.…”

Fiber-Embedded Metallic Materials: From Sensing towards Nervous Behavior

“…This permits the reduction of the required amplitude, and thus the necessary matrix plastic flow [40]. Channels were created in the samples using fiber laser irradiation (Figure 10a).…”

New concept to aid efficient fibre integration into metal matrices during ultrasonic consolidation

“…19 The channel production process has been described elsewhere. 20 The samples for the SPI 200 W fibre laser were processed using a power of 140 W, a speed of 275 mm/min and a nitrogen gas pressure of 0.6 MPa. The samples for the Trumpf TruFiber 300 W laser were processed using a power of 250 W, a traverse speed of 200 mm/min and an air gas pressure of 0.8 MPa.…”

“…This was due to the flow of the melt and has been previously discussed. 20 In order to explore the influences of the channel, one-sided shoulder and fibre orientation, which would possibly influence plastic flow behaviour and bond formation during UC, 8 samples containing channels perpendicular and parallel to the welding direction were considered. In Figure 4, both channel types are displayed.…”