In order to introduce high amounts of hydrogen in aluminum and aluminum alloys, a new method of hydrogen charging was developed, called the friction in water procedure.
A new method of hydrogen charging of aluminum was developed by means of a friction in water (FW) procedure. This procedure can easily introduce high amounts of hydrogen into aluminum based on the chemical reaction between water and non-oxide coated aluminum.
In general, aluminum base alloys have higher resistance to environmental hydrogen embrittlement than steel. The high resistance to hydrogen embrittlement of aluminum alloys is due to oxide films on the alloy surface blocking hydrogen entry. To evaluate and compare the high embrittlement sensitivity between aluminum alloys, hydrogen charging is usually performed prior to mechanical testing1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17. However, it is known that hydrogen charging aluminum is not easy, even when utilizing hydrogen charging methods such as cathodic charging15, slow strain rate deformation under humid air16, or hydrogen plasma gas charging17. The difficulty of hydrogen charging aluminum alloys is also due to the oxide films on the aluminum alloy surface. We postulated that higher amounts of hydrogen could be introduced into aluminum alloys if we could remove the oxide film continuously in water. Thermodynamically18, pure aluminum without oxide film reacts easily with water and generates hydrogen. Based on this, we have developed a new method of hydrogen charging of aluminum alloys based on the chemical reaction between water and non-oxide aluminum. This method is able to add high amounts of hydrogen into aluminum alloys in a simple way.
One important aspect of the FW procedure is the attachment of the two specimens to the magnetic stirrer. Because the center of the stirrer bar becomes the non-friction zone, it is best to avoid the attachment of the specimens at the center of the stirrer bar.
Control of the rotation speed of the stirrer bar is also important. When the speed is more than 240 rpm, it becomes difficult to maintain the reaction vessel on the stage of the magnetic stirrer. When the FW procedure is carried out at hi…
The authors have nothing to disclose.
This work was financially supported in part by The Light Metal Educational Foundation, Inc., Osaka, Japan
Air furnace | GC | QC-1 | |
Aluminum alloy plates | Kobe Steel | Al/1.0 mass% Mg/0.8 mass% Si | |
Electric balance | A&D | HR-200 | |
Glass container | Custom made | ||
Magnetic stirrer | CORNING | PC-410D | |
Optical Comparator | NIKON | V-12B | |
pH meter | Sato Tech | PH-230SDJ | |
Quartz tube | Custom made | ||
Rotary polishing machine | IMT | IM-P2 | |
Secondary electrom microscope | JOEL | JSM-5310LV | |
Sensor gas chromatograph | FIS Inc. | SGHA | |
Silicon carbide emery paper | IMT | 531SR | |
Tensile testing machine | Toshin Kogyo | SERT-5000-C | |
Tubular furnace | Honma Riken | Custom made |