Advanced Joining Technologies for Automotive Lightweight Structures: Novel Joining Processes
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Shaping and Forming Committee
Program Organizers: Yan Huang, Brunel University London; Carla Barbatti, Constellium
Monday 8:30 AM
March 20, 2023
Room: 29C
Location: SDCC
Session Chair: Shouxun Ji, Brunel University London
8:30 AM Invited
Enabling Multimaterial Joining in Lightweight Automotive Structures Using Novel High Velocity Riveting Process: Benjamin Schuessler1; Daniel Ramirez-Tamayo1; Lei Li1; Ayoub Soulami1; Sridhar Niverty1; Xiaolong Ma1; Darrel Herling1; Vineet Joshi1; 1Pacific Northwest National Laboratory
To meet energy reduction goals, new lightweight multimaterials are being used for automotive and transportation industries. Current joining methods for automotive industries involve clinching or a steel self-pierce rivet, with the latter introducing a recyclability challenge. To address the challenges associated with joining dissimilar metals and respective recyclability of automotive components, we introduce high velocity riveting (HiVe), a dynamic joining technique that forms a metallurgical bond in solid phase while simultaneously forming a mechanical interlock. Aluminum alloys AA6061-T6 and AA5052-H32 were bonded utilizing varying die geometries along with dissimilar DP590 steel to aluminum material stacks. Advanced electron microscopy and x-ray tomography were used to investigate the bonding interfaces and determine the influence of the process parameters on joint performance. Lapshear testing of HiVe joints resulted in up to 500% increase in max loading and up to 72% increase in elongation compared clinching of comparable material stacking.
9:00 AM Invited
Impact Welding of an Automotive Component with Vaporizing Foil Actuator: Yu Mao1; Brian Thurston1; Anupam Vivek1; Glenn Daehn1; 1The Ohio State University
Lightweighting of an all-steel engine cradle was accomplished by converting to a multi-material structure containing stamped 5052 grade aluminum in addition to HSLA 340 steel. The components were impact welded together by several vaporizing foil actuator welds made by a hydraulically closing weld head energized by a capacitor bank with a maximum charging energy of 4.2kJ. The welds were tested at the coupon scale and exceeded the requirements under simulated static and cyclic loading conditions. The welded interface was heterogeneous in structure as well as composition with some regions being flat and some being wavy, as is typical in impact welds. Vaporizing foil actuator welding will be presented in terms of the basic process, equipment, consumables and versatility in weldable material combinations and configurations. The particular application of welding up an engine cradle will be discussed from the perspective of material selection, mechanical testing and characterization of the welds.
9:30 AM
Adhesive Bonding of Lightweight Multi-materials with Surface Modifications: Yong Chae Lim1; Nihal Kanbargi1; Zeyang Yu1; Bradley Lokitz1; Jiheon Jun1; Yi Feng Su1; Amit Naskar1; Zhili Feng1; 1Oak Ridge National Laboratory
Adhesive bonding of lightweight multi-materials, including high strength aluminum alloy, carbon fiber reinforced composites and advanced high strength steels, were investigated as a viable joining technique for lightweight vehicle applications. In this presentation, different surface modifications methods were applied on the selected substrates to enhance the bonding between the adhesive and material substrates so that the joining interface can achieve higher adhesive bonding strength. Optical and advanced characterization techniques were used to study changes of morphology, local chemistry, and/or surface energy on the substrates before and after surface modification. Lap shear tensile testing was performed to study the bonding strength before and after corrosion exposure performed per ASTM B117. This presentation will report the corrosion attacks adjacent to the bonded lap joint area and the change of boding strength with increasing corrosion exposure time.
9:55 AM Break
10:10 AM
Joint Strength Optimization of Single-lap Al 5052-H36 Adhesively Bonded for Off-road Vehicle Chassis Components: Marzieh Nodeh1; Ahmed Maslouhi1; Alain Desrochers1; 1Universite de Sherbrooke
The main objective of this work is to define optimum values for key parameters affecting the strength of adhesively bonded Al 5052-H36 joints. These parameters are adhesive type, curing temperature, and geometrical parameters. To evaluate the effect of these parameters on the performance of bonded joints, single-lap joint coupons were prepared and tested under tension. The adhesives 852/25GB and Ep 5089, were studied to analyze the effect of the polymer type on the mechanical behavior of bonded joints. The effect of geometrical parameters and curing temperature of adhesive were investigated for joints assembled with 852/25GB. 852/25GB makes weaker joints and shows cohesive failure, while EP 5089 adhesive resulted in stronger joints and interface failure. Samples exposed to heating cycles generated the strongest joints compared to those cured @ RT and 35 ̊C. Increasing overlap length, decreasing adhesive thickness, and the presence of spew fillet improved the joint resistance.
10:35 AM
Ultrasonically Assisted Resistance Spot Welding of Multiple Thin Al Foil Stacks for Battery Cell Joining: Ho Kwon1; Xun Liu1; 1The Ohio State University
Joining multiple thin foils of current collectors to a conductive tab is one of the critical processes to ensure battery life. In this study, multiple thin pure aluminum foils with layer number 25 to 100 are joined to tab by a recently developed ultrasonically assisted resistance spot welding (URW) hybrid process. In the weld schedule, the ultrasonic vibration was triggered by preheating current, continued during the main weld current, and stopped when current is off. Under the same electrical pulse parameters, URW welds show improved mechanical properties and microstructure than conventional resistance spot welds (RSW) . Lap shear tensile tests and microhardness mapping showed higher strength of URW welds. In addition, the maximum force before the lap shear tensile failure increases linearly proportional to the number of foil layers in URW condition. Moreover, enlarged nugget size, as well as reduced porosity, were observed at the URW weld cross section.
11:00 AM
Investigation of Metal Mixing in Laser Keyhole Welding of Dissimilar Metals: Wenkang Huang1; Wenda Tan1; 1The University of Michigan
In this study, the metal mixing process in laser keyhole welding of dissimilar metals was investigated with a combination of experimental and modeling approaches. The parametric experimental study was conducted to reveal the effects of laser power, welding speed, and heat input on the metal mixing in the fusion zone. Ex-situ energy-dispersive X-ray spectroscopy element mapping was used to characterize the metal mixing status in the fusion zone. To investigate the underlying physics of the welding process, a numerical model was developed to simulate the heat transfer, fluid flow, and metal mixing in the molten pool. The numerical results demonstrated that the metal mixing behavior was strongly affected by the recoil pressure, Marangoni force, and molten pool lifetime. The influence of different welding parameters on those factors was studied based on the simulation and experimental results.