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

Author(s):  
S. Masurtschak ◽  
R. J. Friel ◽  
A. Gillner ◽  
J. Ryll ◽  
R. A. Harris

Ultrasonic consolidation (UC) has been proven to be a suitable method for fiber embedment into metal matrices. To aid successful embedment of high fiber volumes and to ensure their accurate positioning, research on producing microchannels in combination with adjacent shoulders formed by distribution of the melt onto unique UC sample surfaces with a fiber laser was carried out. This paper investigated the effect of the laser on the microstructure surrounding the channel within an Al 3003-H18 sample. The heat input and the extent of the heat-affected zone (HAZ) from one and multiple passes was examined. The paper explored the influence of air, as an assist gas, on the shoulders and possible oxide formation with regards to future bonding requirements during UC. The authors found that one laser pass resulted in a keyhole-shaped channel filled with a mixture of aluminum and oxides and a symmetrical HAZ surrounding the channel. Multiple passes resulted in the desired channel shape and a wide HAZ which appeared to be an eutectic microstructure. The distribution of molten material showed oxide formation all along the channel outline and especially within the shoulder.

2014 ◽  
Vol 41 (12) ◽  
pp. 1203001
Author(s):  
许飞 Xu Fei ◽  
杨璟 Yang Jing ◽  
巩水利 Gong Shuili ◽  
毛智勇 Mao Zhiyong ◽  
芦伟 Lu Wei

2016 ◽  
Vol 25 (43) ◽  
pp. 7-19 ◽  
Author(s):  
Minerva Dorta-Almenara ◽  
María Cristina Capace

Gas Tungsten Arc Welding (GTAW) is one of the most used methods to weld aluminum. This work investigates the influence of welding parameters on the microstructure and mechanical properties of GTAW welded AA6105 aluminum alloy joints. AA6105 alloy plates with different percent values of cold work were joined by GTAW, using various combinations of welding current and speed. The fusion zone, in which the effects of cold work have disappeared, and the heat affected zone of the welded samples were examined under optical and scanning electron microscopes, additionally, mechanical tests and measures of Vickers microhardness were performed. Results showed dendritic morphology with solute micro- and macrosegregation in the fusion zone, which is favored by the constitutional supercooling when heat input increases. When heat input increased and welding speed increased or remained constant, greater segregation was obtained, whereas welding speed decrease produced a coarser microstructure. In the heat affected zone recrystallization, dissolution, and coarsening of precipitates occurred, which led to variations in hardness and strength.


2008 ◽  
Author(s):  
Naoyuki Matsumoto ◽  
Yousuke Kawahito ◽  
Masami Mizutani ◽  
Seiji Katayama

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Huijie Liu ◽  
Yunqiang Zhao ◽  
Xingye Su ◽  
Lilong Yu ◽  
Juncai Hou

2A12-T4 aluminum alloy was friction stir spot welded, and the microstructural characteristics and mechanical properties of the joints were investigated. A softened microstructural region existed in the joint, and it consisted of stir zone (SZ), thermal mechanically affected zone (TMAZ), and heat affected zone (HAZ). The minimum hardness was located in TMAZ, and the average hardness value in SZ can be improved by appropriately increasing welding heat input. The area of complete bonding region at the interface increased with increasing welding heat input because more interface metals were mixed. In a certain range of FSSW parameters, the tensile shear failure load of the joint increased with increasing rotation speed, but it decreased with increasing plunge rate or decreasing shoulder plunging depth. Two kinds of failure modes, that is, shear fracture mode and tensile-shear mixed fracture mode, can be observed in the tensile shear tests, and the joint that failed in the tensile-shear mixed fracture mode possessed a high carrying capability.


2002 ◽  
Vol 52 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Takeshi SAWAI ◽  
Koichi OGAWA ◽  
Hiroshi YAMAGUCHI ◽  
Hiizu OCHI ◽  
Yoshiaki YAMAMOTO ◽  
...  

2011 ◽  
Vol 110-116 ◽  
pp. 3191-3198
Author(s):  
Sadegh Moeinifar

The high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The Gleeble thermal simulated process involved heating the steel specimens to the peak temperature of 1400 °C, with constant cooling rates of 3.75 °C/s and 2 °C/s to room temperature. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone regions. The martensite/austenite constituents were obtained by a combination of field emission scanning electron microscopes and image analysis software The Charpy absorbed energy of specimens was assessed using Charpy impact testing at-50 °C. Brittle particles, such as martensite/austenite constituent along the grain boundaries, can make an easy path for crack propagation. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.


2018 ◽  
Vol 53 (11) ◽  
pp. 1459-1473 ◽  
Author(s):  
Shiva Dayal Rao B ◽  
Abhijeet Sethi ◽  
Alok Kumar Das

In the present investigation, a continuous wave fiber laser with maximum power of 400 W was used to cut a glass fiber reinforced plastic sheet of 4.56 mm thickness using Nitrogen as assisting gas. The influence processing parameters such as laser irradiance, gas pressure, and cutting speed on the cut surface quality were investigated by using response surface methodology. The different responses of laser cut surface such as upper kerf width, taper percentage along the cut depth, and heat-affected zone on the top surface were measured to analyze the influence of input process parameters on the responses. A statistical analysis on the obtained results was conducted and found that the optimum values of different input process parameters were laser irradiance: 8.28 × 105 watt/cm2, cutting speed: 600 mm/min and assisting gas pressure: 7.84 bar. The corresponding values of responses were upper kerf width: 177.4 µm, taper 0.73%, and heat-affected zone on top surface: 109.23 µm. The confirmation experiments were conducted with the obtained optimum parameter setting and observed that the predicted values and experimental values for upper kerf width, taper percentage and top surface heat-affected zone were within the error limits of 2.52%, 1.84%, and 0.45%, respectively. Furthermore, damages like loose fibers, interlayer fractures, evaporation of matrix material and fiber breakages were observed.


2018 ◽  
Vol 937 ◽  
pp. 61-67
Author(s):  
Yu Jie Li ◽  
Jin Wei Lei ◽  
Xuan Wei Lei ◽  
Oleksandr Hress ◽  
Kai Ming Wu

Utilizing submerged arc welding under heat input 50 kJ/cm on 60 mm thick marine engineering structure plate F550, the effect of preheating and post welding heat treatment on the microstructure and impact toughness of coarse-grained heat-affected zone (CGHAZ) has been investigated. The original microstructure of the steel plate is tempered martensite. The yield and tensile strength is 610 and 660 MPa, respectively. The impact absorbed energy at low temperature (-60 °C) at transverse direction reaches about 230~270 J. Welding results show that the preheating at 100 °C did not have obvious influence on the microstructure and toughness; whereas the tempering at 600 °C for 2.5 h after welding could significantly reduce the amount of M-A components in the coarse-grained heat-affected zone and thus improved the low temperature impact toughness.


2015 ◽  
Vol 55 (9) ◽  
pp. 2018-2026 ◽  
Author(s):  
Takako Yamashita ◽  
Junji Shimamura ◽  
Kenji Oi ◽  
Masayasu Nagoshi ◽  
Katsunari Oikawa ◽  
...  

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