Pulsed Nd-YAG laser deposition of TiN and TiAlN coating

AbstractThis paper demonstrates the feasibility of generating a thin clad coating of TiN and TiAlN on SS304 base material by using the pulsed Nd-YAG laser. In the experiment TiN based coating was created with and without the addition of Al-powder. In the post processing, a precision grinder was employed to smoothen the top surface. SEM, XRD and EDS analysis were employed to study the surface topography etc. Microhardness mapping was performed at various points across the surface. The results show the average microhardness of the coating deposited with TiN is lower (1035 HV) than that of using Al-mixed powder (1264 HV)

Beugungseffekte bei Materialbearbeitung mit Laserstrahlen

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Laser and surface processes of NiTi shape memory elements for micro-actuation

In the current microtechnology for actuation field, shape memory alloys (SMA) are considered one of the best candidates for the production of mini/micro devices thanks to their high power-to-weight ratio as function of the actuator weight and hence for their capability of generating high mechanical performance in very limited spaces. In the microscale the most suitable conformation of a SMA actuator is given by a planar wavy formed arrangement, i.e., the snake-like shape, which allows high strokes, considerable forces, and devices with very low sizes. This uncommon and complex geometry becomes more difficult to be realized when the actuator dimensions are scaled down to micrometric values. In this work, micro-snake-like actuators are laser machined using a nanosecond pulsed fiber laser, starting from a 120-μm-thick NiTi sheet. Chemical and electrochemical surface polishes are also investigated for the removal of the thermal damages of the laser process. Calorimetric and thermo-mechanical tests are accomplished to assess the NiTi microdevice performance after each step of the working process. It is shown that laser machining has to be followed by some post-processes in order to obtain a micro-actuator with good thermo-mechanical properties