The double-edge effect of second-phase particles on the recrystallization behaviour and associated mechanical properties of metallic materials

Self-piercing riveting (SPR) is a cold mechanical joining process used to join two or more sheets of materials by driving a rivet piercing through the top sheet or the top and middle sheets and subsequently lock into the bottom sheet under the guidance of a suitable die. SPR is currently the main joining method for aluminium and mixed-material lightweight automotive structures. SPR was originated half century ago, but it only had significant progress in the last 25 years due to the requirement of joining lightweight materials, such as aluminium alloy structures, aluminium-steel structures and other mixed-material structures, from the automotive industry. Compared with other conventional joining methods, SPR has many advantages including no pre-drilled holes required, no fume, no spark and low noise, no surface treatment required, ability to join multi-layer materials and mixed materials and ability to produce joints with high static and fatigue strengths. In this paper, research investigations that have been conducted on self-piercing riveting will be extensively reviewed. The current state and development of SPR process is reviewed and the influence of the key process parameters on joint quality is discussed. The mechanical properties of SPR joints, the corrosion behaviour of SPR joints, the distortion of SPR joints and the simulation of SPR process and joint performance are reviewed. Developing reliable simulation methods for SPR process and joint performance to reduce the need of physical testing has been identified as one of the main challenges.

/pdf/self-piercing-riveting-a-review-2j1byq6md3.pdf

Self-piercing riveting-a review

https://digital.csic.es/bitstream/10261/94988/1/Wheathering%20steels.pdf

Weathering steels: From empirical development to scientific design. A review

Nickel-stabilized hexagonal (Cu,Ni)6Sn5 in Sn-Cu-Ni lead-free solder alloys

Characterization of interfacial microstructures in 3003 aluminum alloy blocks fabricated by ultrasonic additive manufacturing

Corrosion characterization of tin–lead and lead free solders in 3.5 wt.% NaCl solution

An automotive battery pack for use in electric vehicles consists of a large number of individual battery cells that are structurally held and electrically connected. Making the required electrical and structural joints represents several challenges, including, joining of multiple and thin highly conductive/reflective materials of varying thicknesses, potential damage (thermal, mechanical, or vibrational) during joining, a high joint durability requirement, and so on. This paper reviews the applicability of major and emerging joining techniques to support the wide range of joining requirements that exist during battery pack manufacturing. It identifies the advantages, disadvantages, limitations, and concerns of the joining technologies. The maturity and application potential of current joining technologies are mapped with respect to manufacturing readiness levels (MRLs). Further, a Pugh matrix is used to evaluate suitable joining candidates for cylindrical, pouch, and prismatic cells by addressing the aforementioned challenges. Combining Pugh matrix scores, MRLs, and application domains, this paper identifies the potential direction of automotive battery pack joining.

Joining Technologies for Automotive Battery Systems Manufacturing

Sn–3.8 wt.% Ag–0.7 wt.% Cu solder was applied to Al–1 wt.% Cu bond pads with an electroless nickel (Ni–P) interlayer as an under bump metallisation (UBM). The microstructure and micromechanical properties were studied after ageing at 80 °C and 150 °C. Two types of intermetallic compounds (IMCs) were identified by electron back-scattered diffraction (EBSD), these being a (Cu, Ni) 6 Sn 5 formed at the solder–UBM interface and Ag 3 Sn in the bulk solder. The (Cu, Ni) 6 Sn 5 layer grew very slowly during the ageing process, with no Kirkendall voids found by scanning electron microscopy (SEM) after ageing at 80 °C. Nano-indentation was used to analyse the mechanical properties of different phases in the solder. Both (Cu, Ni) 6 Sn 5 and Ag 3 Sn were harder and more brittle than the β-Sn matrix of the Sn–Ag–Cu alloy. The branch-like morphology of the Ag 3 Sn IMC, especially at the solder–UBM interface, could ultimately be detrimental to the mechanical integrity of the solder when assembled in flip-chip joints.

Characteristics of intermetallics and micromechanical properties during thermal ageing of Sn–Ag–Cu flip-chip solder interconnects

SiC fibres and single mode (SM) optical fibres were successfully embedded in Al alloys matrices through ultrasonic consolidation (UC). The plastic flow of Al alloy matrices was visualized after anodization by optical microscopy with polarized light. Grain and sub-grain sizes of Al alloys before and after UC and work hardening of matrices due to plastic flow during UC process, were studied. The results show that UC process increases the hardness of alloy matrices, especially at regions proximal to fibres, with work hardening following the Hall–Petch relationship for both grains and sub-grains. During UC process, work hardening is mainly caused by bulk plastic deformation with no significant effect from friction at foil/foil interface. For the consolidated materials tested, work hardening in a 3003 O matrix is higher than that in a 6061 O matrix. In addition, plastic deformation of a 3003 O matrix in SM fibre embedded samples is smaller than that in SiC fibre embedded samples, which may have been influenced by the different embedding processes.

Dezhi Li

Papers

Corrosion characterization of tin–lead and lead free solders in 3.5 wt.% NaCl solution

Self-piercing riveting-a review

Joining Technologies for Automotive Battery Systems Manufacturing

Characteristics of intermetallics and micromechanical properties during thermal ageing of Sn–Ag–Cu flip-chip solder interconnects

Plastic flow and work hardening of Al alloy matrices during ultrasonic consolidation fibre embedding process