Engineers from Pacific Northwest National Laboratory (PNNL), Richland, Wash., discussed a friction stir welding technique known as Friction Stir Interlocking in a presentation at MS&T 2019 in Portland, Oregon.
The Friction Stir Interlocking technique was developed to fabricate joints between magnesium and carbon-fiber reinforced polymers (CFRP) for automotive applications. The process involves introducing pre-machined interlocking features made of magnesium inserts into the CFRP part, while minimizing polymer degradation. Design of the interlocking parts and welding tools was optimized. As part of the development, mechanical properties of welded joints were evaluated with different test methods.
Requirements to reduce fuel consumption and carbon dioxide release in the automobile industry necessitate lightweight structural materials such as magnesium alloys and CFRP. Magnesium alloys have the lowest density among all the structural alloys; CFRP possesses an even higher strength-to-weight ratio comparatively. A mechanically reliable joint between magnesium alloys and CFRP can decrease vehicle weight and boost design flexibility in the automotive industry. However, joining between metals and polymers is challenging due to the large differences in their physical, chemical, and mechanical properties.
Title: Joining of Magnesium to Carbon Fiber Reinforced Polymers using Friction Stir Interlocking technique
Authors: Tianhao Wang; Piyush Upadhyay; Scott Whalen; Keerti Kappagantula; Pacific Northwest National Laboratory
