Reza Beygi is an Associate Professor at Arak University, Iran, specializing in welding metallurgy of dissimilar materials, with a focus on process, microstructure, and mechanical properties. As principal investigator in the Advanced Joining Processes (AJP) group at the University of Porto under the supervision of Professor Lucas F.M. da Silva for three years, he has driven innovations in joining dissimilar metals, resulting in numerous high-impact publications and books. Eduardo André de Sousa Marques is an Associate Professor at the University of Porto and an investigator at INEGI. His research focuses on mechanical behavior, extreme condition testing, and numerical modeling of welded and bonded joints. With over 230 published articles and books, his contributions to materials science and joining technologies are widely recognized. Ricardo João Camilo Carbas is a Post-doctoral Researcher at INEGI specializing in adhesively bonded joints, welding and joining by forming. He has published 245 articles and holds six patents in material joining. A member of several editorial boards, he consults for major companies and organizes international conferences on materials and advanced joining processes. Lucas Filipe Martins da Silva is a Full Professor in Mechanical Engineering at the University of Porto, Portugal. He has established and leads the Advanced Joining Processes Unit of INEGI, carrying out fundamental and applied research on multiple joining technologies. He has published over 400 research articles and 43 books. He is the Editor-in-Chief of multiple academic journals and has organized international conferences on advanced joining technologies.

• Preface viiList of Abbreviations ix1 Aluminum Alloys: Fundamentals of Welding Metallurgy 11.1 Introduction 11.1.1 Aluminum–Copper Alloys 41.1.2 Aluminum–Zinc–Magnesium Alloys 41.1.3 Aluminum–Magnesium–Silicium 41.1.4 Aluminum–Lithium Alloys 51.2 Weldability 51.2.1 Aluminum Oxide 61.2.2 Hydrogen and Pore Formation 71.2.2.1 Effects of Porosity on the Mechanical Behavior 101.2.3 Hot Cracking 101.3 Thermal Cycle and Its Effect on the Weld Zone 231.4 Welding of Aluminum to Other Metals 30References 312 Arc Welding Processes 372.1 Introduction 372.2 Processes 382.2.1 TIG Welding 382.2.2 Plasma Arc Welding 392.2.3 MIG Welding 402.3 Modifications to the Processes 422.3.1 Negative-Pole and Positive-Pole TIG Welding 422.3.2 Keyhole TIG (K-TIG) Welding 422.3.3 Activated-Flux TIG (A-TIG) Welding 442.3.4 Double-Wire MIG Welding 442.3.5 Indirect Electric Arc 462.3.6 Cold Metal Transfer (CMT) Welding 472.3.7 Positive-Pole Plasma Welding 472.3.8 Hyperbaric Welding 482.4 Hybrid Welding 482.4.1 Plasma-MIG Welding 492.4.2 TIG-MIG Welding 512.5 Protective Gases 522.6 Filler Material 532.7 Grain Refinement in the Weld 532.8 Grain Structure 592.9 Defects During Arc Welding 602.9.1 Segregation 602.9.2 Smut 612.9.3 Pores 622.9.4 Hot Cracking 622.10 Welding of Dissimilar Metals 642.11 Simulation of the Arc Welding Processes 67References 723 Beam Welding Processes 833.1 Introduction 833.2 Laser Systems 873.3 Defects Formation During Laser Welding of Al Alloys 883.3.1 Mechanism of Pore Formation 883.3.2 Hot Cracking in Laser Welding 933.4 Shielding Gases in Laser Welding 963.5 Modifications to Laser Welding of Al 983.5.1 Multi-spot Laser Beam Welding 983.5.2 Micro-laser Welding 993.5.3 Pulsed Laser Beam Welding 993.5.4 Hybrid Laser Welding 1033.5.5 Oscillation Laser Beam Welding 1043.5.6 Vibration-Assisted Laser Beam Welding 1053.5.7 Hot-Wire Laser Welding 1063.6 Special Cases of Al Welding 1073.6.1 Additive Manufacturing 1073.6.2 Cast Aluminum 1073.6.3 Welding of Aluminum to Dissimilar Materials 1083.7 Simulation of Laser Welding 109References 1154 Resistance Welding Process 1254.1 Introduction 1254.2 Weld Zones 1314.2.1 Nugget Zone 1314.2.2 Thermo-Mechanically Affected Zone (TMAZ) 1334.3 Defects During RSW of Al Alloys 1354.4 RSW of Dissimilar Aluminum Alloys 1374.5 RSW of Al to Dissimilar Metals 1394.6 Modifications to RSW for Welding Al Alloys 1444.7 Simulation of the Process 1494.8 Evaluation of the Joints 152References 1555 Solid-State Welding Process 1635.1 Introduction 1635.2 FSW of Al Alloys 1645.3 FSW of Al-Matrix Composites 1725.4 FSW of Al to Dissimilar Materials 1755.5 Joint Design 1805.6 Simulation of the Process 184References 186Index 193

Reza Beygi is an Associate Professor at Arak University, Iran, specializing in welding metallurgy of dissimilar materials, with a focus on process, microstructure, and mechanical properties. As principal investigator in the Advanced Joining Processes (AJP) group at the University of Porto under the supervision of Professor Lucas F.M. da Silva for three years, he has driven innovations in joining dissimilar metals, resulting in numerous high-impact publications and books. Eduardo André de Sousa Marques is an Associate Professor at the University of Porto and an investigator at INEGI. His research focuses on mechanical behavior, extreme condition testing, and numerical modeling of welded and bonded joints. With over 230 published articles and books, his contributions to materials science and joining technologies are widely recognized. Ricardo João Camilo Carbas is a Post-doctoral Researcher at INEGI specializing in adhesively bonded joints, welding and joining by forming. He has published 245 articles and holds six patents in material joining. A member of several editorial boards, he consults for major companies and organizes international conferences on materials and advanced joining processes. Lucas Filipe Martins da Silva is a Full Professor in Mechanical Engineering at the University of Porto, Portugal. He has established and leads the Advanced Joining Processes Unit of INEGI, carrying out fundamental and applied research on multiple joining technologies. He has published over 400 research articles and 43 books. He is the Editor-in-Chief of multiple academic journals and has organized international conferences on advanced joining technologies.

• Preface viiList of Abbreviations ix1 Aluminum Alloys: Fundamentals of Welding Metallurgy 11.1 Introduction 11.1.1 Aluminum–Copper Alloys 41.1.2 Aluminum–Zinc–Magnesium Alloys 41.1.3 Aluminum–Magnesium–Silicium 41.1.4 Aluminum–Lithium Alloys 51.2 Weldability 51.2.1 Aluminum Oxide 61.2.2 Hydrogen and Pore Formation 71.2.2.1 Effects of Porosity on the Mechanical Behavior 101.2.3 Hot Cracking 101.3 Thermal Cycle and Its Effect on the Weld Zone 231.4 Welding of Aluminum to Other Metals 30References 312 Arc Welding Processes 372.1 Introduction 372.2 Processes 382.2.1 TIG Welding 382.2.2 Plasma Arc Welding 392.2.3 MIG Welding 402.3 Modifications to the Processes 422.3.1 Negative-Pole and Positive-Pole TIG Welding 422.3.2 Keyhole TIG (K-TIG) Welding 422.3.3 Activated-Flux TIG (A-TIG) Welding 442.3.4 Double-Wire MIG Welding 442.3.5 Indirect Electric Arc 462.3.6 Cold Metal Transfer (CMT) Welding 472.3.7 Positive-Pole Plasma Welding 472.3.8 Hyperbaric Welding 482.4 Hybrid Welding 482.4.1 Plasma-MIG Welding 492.4.2 TIG-MIG Welding 512.5 Protective Gases 522.6 Filler Material 532.7 Grain Refinement in the Weld 532.8 Grain Structure 592.9 Defects During Arc Welding 602.9.1 Segregation 602.9.2 Smut 612.9.3 Pores 622.9.4 Hot Cracking 622.10 Welding of Dissimilar Metals 642.11 Simulation of the Arc Welding Processes 67References 723 Beam Welding Processes 833.1 Introduction 833.2 Laser Systems 873.3 Defects Formation During Laser Welding of Al Alloys 883.3.1 Mechanism of Pore Formation 883.3.2 Hot Cracking in Laser Welding 933.4 Shielding Gases in Laser Welding 963.5 Modifications to Laser Welding of Al 983.5.1 Multi-spot Laser Beam Welding 983.5.2 Micro-laser Welding 993.5.3 Pulsed Laser Beam Welding 993.5.4 Hybrid Laser Welding 1033.5.5 Oscillation Laser Beam Welding 1043.5.6 Vibration-Assisted Laser Beam Welding 1053.5.7 Hot-Wire Laser Welding 1063.6 Special Cases of Al Welding 1073.6.1 Additive Manufacturing 1073.6.2 Cast Aluminum 1073.6.3 Welding of Aluminum to Dissimilar Materials 1083.7 Simulation of Laser Welding 109References 1154 Resistance Welding Process 1254.1 Introduction 1254.2 Weld Zones 1314.2.1 Nugget Zone 1314.2.2 Thermo-Mechanically Affected Zone (TMAZ) 1334.3 Defects During RSW of Al Alloys 1354.4 RSW of Dissimilar Aluminum Alloys 1374.5 RSW of Al to Dissimilar Metals 1394.6 Modifications to RSW for Welding Al Alloys 1444.7 Simulation of the Process 1494.8 Evaluation of the Joints 152References 1555 Solid-State Welding Process 1635.1 Introduction 1635.2 FSW of Al Alloys 1645.3 FSW of Al-Matrix Composites 1725.4 FSW of Al to Dissimilar Materials 1755.5 Joint Design 1805.6 Simulation of the Process 184References 186Index 193

Reza Beygi is an Associate Professor at Arak University, Iran, specializing in welding metallurgy of dissimilar materials, with a focus on process, microstructure, and mechanical properties. As principal investigator in the Advanced Joining Processes (AJP) group at the University of Porto under the supervision of Professor Lucas F.M. da Silva for three years, he has driven innovations in joining dissimilar metals, resulting in numerous high-impact publications and books. Eduardo André de Sousa Marques is an Associate Professor at the University of Porto and an investigator at INEGI. His research focuses on mechanical behavior, extreme condition testing, and numerical modeling of welded and bonded joints. With over 230 published articles and books, his contributions to materials science and joining technologies are widely recognized. Ricardo João Camilo Carbas is a Post-doctoral Researcher at INEGI specializing in adhesively bonded joints, welding and joining by forming. He has published 245 articles and holds six patents in material joining. A member of several editorial boards, he consults for major companies and organizes international conferences on materials and advanced joining processes. Lucas Filipe Martins da Silva is a Full Professor in Mechanical Engineering at the University of Porto, Portugal. He has established and leads the Advanced Joining Processes Unit of INEGI, carrying out fundamental and applied research on multiple joining technologies. He has published over 400 research articles and 43 books. He is the Editor-in-Chief of multiple academic journals and has organized international conferences on advanced joining technologies.

• Preface viiList of Abbreviations ix1 Aluminum Alloys: Fundamentals of Welding Metallurgy 11.1 Introduction 11.1.1 Aluminum–Copper Alloys 41.1.2 Aluminum–Zinc–Magnesium Alloys 41.1.3 Aluminum–Magnesium–Silicium 41.1.4 Aluminum–Lithium Alloys 51.2 Weldability 51.2.1 Aluminum Oxide 61.2.2 Hydrogen and Pore Formation 71.2.2.1 Effects of Porosity on the Mechanical Behavior 101.2.3 Hot Cracking 101.3 Thermal Cycle and Its Effect on the Weld Zone 231.4 Welding of Aluminum to Other Metals 30References 312 Arc Welding Processes 372.1 Introduction 372.2 Processes 382.2.1 TIG Welding 382.2.2 Plasma Arc Welding 392.2.3 MIG Welding 402.3 Modifications to the Processes 422.3.1 Negative-Pole and Positive-Pole TIG Welding 422.3.2 Keyhole TIG (K-TIG) Welding 422.3.3 Activated-Flux TIG (A-TIG) Welding 442.3.4 Double-Wire MIG Welding 442.3.5 Indirect Electric Arc 462.3.6 Cold Metal Transfer (CMT) Welding 472.3.7 Positive-Pole Plasma Welding 472.3.8 Hyperbaric Welding 482.4 Hybrid Welding 482.4.1 Plasma-MIG Welding 492.4.2 TIG-MIG Welding 512.5 Protective Gases 522.6 Filler Material 532.7 Grain Refinement in the Weld 532.8 Grain Structure 592.9 Defects During Arc Welding 602.9.1 Segregation 602.9.2 Smut 612.9.3 Pores 622.9.4 Hot Cracking 622.10 Welding of Dissimilar Metals 642.11 Simulation of the Arc Welding Processes 67References 723 Beam Welding Processes 833.1 Introduction 833.2 Laser Systems 873.3 Defects Formation During Laser Welding of Al Alloys 883.3.1 Mechanism of Pore Formation 883.3.2 Hot Cracking in Laser Welding 933.4 Shielding Gases in Laser Welding 963.5 Modifications to Laser Welding of Al 983.5.1 Multi-spot Laser Beam Welding 983.5.2 Micro-laser Welding 993.5.3 Pulsed Laser Beam Welding 993.5.4 Hybrid Laser Welding 1033.5.5 Oscillation Laser Beam Welding 1043.5.6 Vibration-Assisted Laser Beam Welding 1053.5.7 Hot-Wire Laser Welding 1063.6 Special Cases of Al Welding 1073.6.1 Additive Manufacturing 1073.6.2 Cast Aluminum 1073.6.3 Welding of Aluminum to Dissimilar Materials 1083.7 Simulation of Laser Welding 109References 1154 Resistance Welding Process 1254.1 Introduction 1254.2 Weld Zones 1314.2.1 Nugget Zone 1314.2.2 Thermo-Mechanically Affected Zone (TMAZ) 1334.3 Defects During RSW of Al Alloys 1354.4 RSW of Dissimilar Aluminum Alloys 1374.5 RSW of Al to Dissimilar Metals 1394.6 Modifications to RSW for Welding Al Alloys 1444.7 Simulation of the Process 1494.8 Evaluation of the Joints 152References 1555 Solid-State Welding Process 1635.1 Introduction 1635.2 FSW of Al Alloys 1645.3 FSW of Al-Matrix Composites 1725.4 FSW of Al to Dissimilar Materials 1755.5 Joint Design 1805.6 Simulation of the Process 184References 186Index 193