Improving Global Quality of Life

Furthermore, in the field of dissimilar combinations of metallic, ceramic and carbon-carbon
materials, the following areas are creating challenges.
Technologies for joining (welding) the above materials by using new pulsed heating methods,
electromagnetic or mechanical effects, and hybrid solid-state joining processes.
New welding consumables in the form of films, foils, powders and pastes, including multilayer
foils, capable of entering into reaction of high-temperature synthesis of intermetallic phases in
local volumes (spaces).
Building of new types of structures from materials with a minimal specific weight, i.e. foam
materials, sandwiches, dissimilar compositions, volumetric billets of typical shapes (cylinders,
cones, hemispheres), ribbed panels and panels with cavities.
Building of armoured and fireproof welded structures through a combined use of dissimilar
materials and their joining methods, as well as compact transformable billets, which can be
transformed into large-volume structures (tanks, compartments, habitable rooms, etc.).
Manufacture of Thermal Protection Systems: Near- and trans-space structures require efficient
thermal protection systems (TPS) to deal with reusable, multi-re-entry vehicles. The selection and
combination of materials for maximum thermal, structural, and weight performance is crucial. The
joining technology that is flying today is over thirty years old. Improvements in materials joining
methods are enabling technologies for advanced flight concepts. Welding, brazing, soldering,
adhesive bonding, and NDE are all pertinent to this field.
Repair: Manufacture, repair, and overhaul continue to be a major driver of joining technology
innovation in the aerospace industry. Repair technologies are driven by two competing factors;
low metallurgical damage to the substrate and high deposition rates. These features, however, are
generally mutually exclusive. This has driven technology innovations such as laser powder buildup,
cold metal transfer and cold spray. There is also a push towards near net shape repair. This is
attaching pre-formed repair elements, reducing the expense of post-deposition machining.
Reducing material usage: Improving material buy-to-fly ratios, is a key element in reducing the
overall costs of manufacture. To this end, welded components are increasingly replacing those
machined out of single blocks of materials. Generally, two penalties are paid for replacing a fully
machined component with a welded one. The first is loss of properties in the weld and heat affected
areas. The second is geometric stability of the final part. New processes, better process control,
better predictive capabilities, etc. will all be necessary to address this new generation of welded
components.
Implementation of low cost manufacturing technologies: Reducing the overall costs of
manufacture continues to be a major driver for technology innovation in the aerospace industry.
To this end, there is increasing interest in standardisation of parts, and subsequent increases
in manufacturing volumes for those components. Higher volumes permit economies of scale. This
has placed focus on higher productivity joining processes. Higher productivity joining ranges from
increased deposition rates with existing processes, to the use of newer approaches. In this regard,
laser processing, resistance welding, etc., with their inherent advantages in higher production
volumes, will see increasing use in aerospace construction.
Development of novel solid-state processes: Manufacturability of hardware through novel solidstate
welding processes offers distinct advantages to the aerospace industry reducing buy-to-fly
ratios and production costs. Ultrasonic additive manufacturing (UAM) is one such technology based
on solid-state welding, joining successive layers of material to produce near net shape hardware.
Producing hardware in this fashion requires minimal material consumption while producing highly
accurate components. Fabrication of such hardware also allows for the development of smart
150 Improving Global Quality of Life Through Optimum Use and Innovation of Welding and Joining Technologies