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- Advanced high strength steels (1)
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- Corrosion (1)
- Crash behaviour (1)
- Fatigue (1)
- Fracture behaviour (1)
- High strength steel (1)
- Hochfester Stahl (1)
- Hybrid bonding (1)
- IUPAC physical and biophysical chemistry division (1)
- Image analysis (1)
- Interlaboratory study (1)
- Lightweight body shell design (1)
- Liquid intrusion (1)
- Macroporous materials (1)
- Mechanical strength (1)
- Mercury prorsimetry (1)
- Nanoporous carbon (1)
- Permeation (1)
- Pore size characterization (1)
- Punktschweißkleben (1)
- Reference isotherm (1)
- Reference porous materials (1)
- Resistance spot welding (1)
- Statistical reconstruction of porous solids (1)
- VAMAS (1)
- Weldbonded joint behaviour (1)
- Weldbonded joints (1)
- Weldbonding (1)
- Weldbonding process reliability (1)
- Widerstandspunktschweißen (1)
Organisationseinheit der BAM
- 6 Materialchemie (1)
- 6.3 Strukturanalytik (1)
In lightweight car body shell mass production, due to requirements on vehicle weight reduction and carbon dioxide emissions, joining of advanced high strength steels (AHSS) with different joining procedures and especially hybrid bonding techniques is becoming more and more important. One of these hybrid bonding techniques is the combination of resistance spot welding and adhesive bonding called weldbonding. One of the important advantages of weldbonded joints in comparison to resistance spot welded joints are the enhanced mechanical properties. To guarantee sufficiently high quality conditions regarding the strength of the weldbonded joints, the influences of the applied adhesive systems and of different base metal combinations are studied. This is carried out for both non-corrosive and corrosive environments and for the choice of different joining parameters settings. In particular, the mechanical behaviour of the weldbonded joints is investigated under quasi-static, impact and fatigue loads. Furthermore, the energy absorption of the weldbonded joints for both non-corrosive and corrosive environments is studied. It is shown that the weldbonded joints possess higher mechanical strengths in all load cases (quasi-static, impact and fatigue). Corrosive attack affects weldbonded joints, and the quasi-static strength is reduced. Resistance spot welded joints are not affected by the corrosive attack, but even after several weeks of corrosive attack, the quasi-static strength of weldbonded joints remains higher than that of resistance spot welded joints.
In the lightweight body shell mass production of automobiles, the application of hybrid bonding techniques becomes more and more important. Especially the combination of adhesive bonding and resistance spot welding called weldbonding is of great importance. The target of this contribution is to show the influence of medium-viscosity and low-viscosity structural adhesives on the process reliability of the weldbonding process and the mechanical properties of the hybrid bonded joints. The given results are based on the application of an epoxy PUR-based, an epoxy resin-based and a rubber-based adhesive system for joining a mild and some different advanced high strength steels (AHSS). It will be shown that both the process reliability of the weldbonding process and the mechanical behaviour of the weldbonded joints are influenced by the combinations of the base metals, the applied adhesive systems and the choice of the joining parameters. The behaviour of the weldbonded joints will be studied under quasi-static and impact loads. The discussion of the metallurgical structure of the weldbonded joints depending on the joining parameters will be given, too. Furthermore, the fatigue behaviour of the weldbonded joints will be studied.
This paper reports the results of an international interlaboratory study sponsored by the Versailles Project on Advanced Materials and Standards (VAMAS) and led by the National Institute of Standards and Technology (NIST) on the measurement of water vapor sorption isotherms at 25 °C on a pelletized nanoporous carbon (BAM-P109, a certified reference material). Thirteen laboratories participated in the study and contributed nine pure water vapor isotherms and four relative humidity isotherms, using nitrogen as the carrier gas. From these data, reference isotherms, along with the 95% uncertainty interval (Uk=2), were determined and are reported in a tabular format.
This document deals with the characterization of porous materials having pore widths in the macropore range of 50 nm to 500 µm. In recent years, the development of advanced adsorbents and catalysts (e.g., monoliths having hierarchical pore networks) has brought about a renewed interest in macropore structures. Mercury intrusionextrusion porosimetry is a well-established method, which is at present the most widely used for determining the macropore size distribution. However, because of the reservations raised by the use of mercury, it is now evident that the principles involved in the application of mercury porosimetry require reappraisal and that alternative methods are worth being listed and evaluated. The reliability of mercury porosimetry is discussed in the first part of the report along with the conditions required for its safe use. Other procedures for macropore size analysis, which are critically examined, include the intrusion of other non-wetting liquids and certain wetting liquids, capillary condensation, liquid permeation, imaging, and image analysis. The statistical reconstruction of porous materials and the use of macroporous reference materials (RMs) are also examined. Finally, the future of macropore analysis is discussed.