Laser post-treatments and plasma-laser hybrid spraying processes are increasingly being used to extend the service life of thermal barrier coatings by making them more resistant to thermal shock. Studies show that laser-induced cracking plays a major role in the improvements achieved. The investigation of such modified layers can be difficult, however, because the stresses associated with metallographic procedures can alter the structural features of segmented microcracks and damage the specimen. In this research, laser treated and laser hybrid sprayed thermal barrier coatings are vacuum impregnated with fluorescent epoxy resins in order to study their microstructure and its relationship with thermal shock resistance. All relevant processes are described along with crack formation behaviors. Paper includes a German-language abstract.

This work investigates the effect of processing parameters on the microstructure and composition of Ni-base alloys produced by laser forming, an additive technique also known as direct metal deposition. The parameters assessed in the study include powder flow rate, traverse speed, laser power, and spot size. In all experiments, a melt pool diameter of 0.3 mm was maintained. The results show that laser formed alloys are similar in structure to conventional wrought alloys with additional peaks formed as a result of the oxidation of active alloying elements. The complex compounds observed on the surface of the laser formed samples disappeared after polishing. Paper includes a German-language abstract.

Laser beam cladding is a versatile method for the deposition of functional surface layers, the generation of prototypes, and the repair welding of components. It is a thermal process characterized by a highly localized energy input. Powder-fed laser cladding is typically done with a CO 2 , Nd:YAG, or diode laser scanned at a speed of 0.3 to 1.5 m/min. The present work investigates the extent to which deposition speed and thermal efficiency can be increased. Using a Nd:YAG laser and high scan rates, functional layers a few tenths of a mm thick are obtained and larger surface areas are processed per unit of time. Paper text in German.

The aim of this investigation is to increase the corrosion and wear resistance of magnesium (Mg) alloys. This paper explains how various coatings applied via plasma powder (PTA) and laser deposition welding processes affect the wear properties of two Mg alloys. It is shown that coating quality depends on the type of Mg used, the composition of the filler materials (matrix and carbides), and welding parameters. The best results for Mg alloys AM50 and AZ31 were obtained with a coating consisting of a composite matrix (AlSi 12 ) with boron carbide additions. Paper text in German.

This paper discusses some of the recent improvements in plasma powder surface build-up welding technology and provides examples of its use in different areas of industry. It describes the coating properties achievable with newly developed filler alloys and how they compare with conventional hardcoats. It also discusses the growing use of manual overlay PTA welding among small and midsize companies and the factors behind it. Paper text in German.

Plasma transferred arc spraying of tungsten carbide coatings can significantly increase the service life of machines and components subject to wear. This paper assesses the effect of such coatings in oil sand processing equipment. It describes the development and testing of the layers used and explains that the extraction and processing of oil sands necessitate continuous testing and ongoing improvement in both materials and processing techniques. Paper includes a German-language abstract.

Titanium aluminide shows good potential for lightweight applications at high temperatures, provided various problems are overcome. The primary problem, low-temperature brittleness, can be resolved through a combination of laser cladding and directional solidification. This paper explains how Ti48Al2Cr alloy is applied and how process parameters must be chosen so that directional solidification occurs. This involves the use of FEM simulations, carried out in parallel with experimental work, to determine temperature gradients and cooling rates at the solidification front and in the melt pool and their effect on solidification structures. Paper text in German.