Advanced Joining Technologies for Automotive Lightweight Structures: Resistance and Ultrasonic Spot Welding Plus (RSW & USW, etc.)
Sponsored by: ACerS Manufacturing Division, TMS Aluminum Committee
Program Organizers: Yan Huang, Brunel University London; Carla Barbatti, Constellium; Yingchun Chen, Dura Automotive Systems
Wednesday 2:00 PM
October 12, 2022
Room: 328
Location: David L. Lawrence Convention Center
Session Chair: Paul Briskham, Atlas Copco IAS UK Ltd; Yan Huang, Brunel University London
2:00 PM
Integrating an Interlayer Technology Approach to Advanced Materials While Resistance Spot Welding: Liya Amanuel1; Bryan Lara1; Antonio Ramirez1; 1The Ohio State University
Advanced materials are increasingly chosen by the automotive industry specifically for the construction of vehicle structures in an effort to achieve energy savings while supporting safety criteria. Attractive candidates to address these interests by the automotive industry are advanced high strength steels (AHSS) and aluminum alloys. Improved ductility, high crashworthiness, and increased strength are all attributed to AHSS. Furthermore, aluminum alloys offer strength and lightweighting to body-in-white designs. Despite these advantages, both of these materials see energy absorption issues during resistance spot welding (RSW). For AHSS-to-AHSS spot welds, limited toughness is observed. Al-to-AHSS spot welds encounter decreases in the strength of the joints due to intermetallic (IMC) formation. Using a well-informed scientific approach, interlayers were selected to improve the weldability of these materials. This approach acts to alter the material’s chemistry for toughness, prevent or minimize IMC formation, induce changes in the RSW process itself, and promote mechanical interlocking.
2:20 PM
Fatigue Analyses of Dissimilar Aluminum-Steel Clinch Joints for Lightweight Construction: Lars Ewenz1; Sebastian Schöne1; Martina Zimmermann2; 1TU Dresden; 2TU Dresden and Fraunhofer Institute for Material and Beam Technology IWS
In this research, the fatigue behavior of a dissimilar aluminum-steel clinch joint is opposed to aluminum-aluminum and steel-steel clinch joints. The cyclic strength is essential in lightweight design approaches, where the design shall push strength limits. The material combination used here, EN AW-6014 and HCT590, offers excellent practical relevance since both materials are widely used in the automotive industry. A first analysis shows that the aluminum-aluminum clinch joint is about 70% weaker than the steel-steel variant, which is not surprising. However, contrary to the expectation that the dissimilar aluminum-steel clinch joint would be in the range of the fatigue properties of the aluminum-aluminum clinch joint, the dissimilar joint achieves even less than 60% of the fatigue strength. SEM and optical microscopy investigations elucidate whether this behavior is caused by the different clinch geometries and the resulting load distribution during shear loading.
2:40 PM
A Novel Approach to Determine Intermetallic Formation and Growth in the Aluminum-Iron System Using Resistance-based Diffusion Couples: Michael Eff1; Wei Zhang2; Jerry Gould1; Antonio Ramirez3; 1EWI; 2The Ohio State University ; 3The Ohio State University
Lightweighting is a key trend across the automotive industry and has led to an ever-growing variety of materials used in a vehicle. To optimize the multi-material benefits, dissimilar materials must be joined. The most common combination is aluminum to steel, which often forms brittle intermetallic compounds (IMC) when joined. IMC kinetics and nucleation data at time scales of typical welding processes do not exist in open literature. This work focuses on the results of a novel rapid resistance-based diffusion couple in the Al-Fe system to generate this much needed kinetics data. The samples were rapidly heated to 375°C and 500°C for times varying from 0.25-s up to 10-s and then quenched. The IMC layers were characterized using both SEM and TEM techniques for composition, morphology and crystal structure. Both short time kinetics plots and a new insight into Fe-Al IMC nucleation mechanism were generated as a result of this work.
3:00 PM
Dissimilar Materials Welding between AA6061 and CFRP Utilizing Vaporizing Foil Actuator Welding: YuHyeong Jeong1; Kyucheol Jeong1; Wonju Lee1; Hyung-gyu Kim1; Jonghun Yoon1; 1Hanyang University
Vaporizing foil actuator welding(VFAW) performs the joining by colliding the two dissimilar materials using high pressure, which generated by vaporizing aluminum foil. To vaporize the aluminum foil, a high-rate transmission of current pulse is applied to the foil and the high vaporization pressure is formed as a result. This pressure pushes the flyer sheet and it collides to the target sheet.By applying VFA welding process, Al6061-T4 and carbon fiber plate were used for target and flyer sheet to attach both materials. A hole was drilled on the carbon fiber and aluminum sheets were located at the top and bottom side of carbon fiber. When the VFAW process was conducted in this setting, the flyer aluminum sheet was collided with other aluminum sheet, by passing through the hole of carbon fiber. As a result, both aluminum sheets were welded, and carbon fiber was bonded with them tightly.