Effects of micro laser sintering process parameters on quality of nickel-titanium single tracks and thin walls

Additive Manufacturing from the Point of View of Materials Research

“…Mechanically produced powder Mechanical shape memory functionality was proven with a force range of 10-100 mN [119] Quality of deposited Ni-Ti was improved by increasing the scanning speed [120] E-PBF PREP atomized powder No visible shape memory and pseudoplastic effect seen [121] The authors did not recommend E-PBF for Ni-Ti alloys. Preheating was required [97] E-PBF process resulted in better tensile properties than L-DED and L-PBF [97,122] PAD Pre-alloyed powder Linear superelasticity [123] Quasi-linear superelasticity with narrow hysteresis [123,124] WAAM Wire High hardness and tensile strength [125] Cu-Al-Ni L-PBF Elemental powders High aluminum content led to dendrites and high hardness [126] Cu-Al-Ni-Mn Gas atomized powder High relative density (>92%) achieved [127][128][129] Reversible martensitic transformation with the formation of β 1 '-martensite [127][128][129] Large strain recovery after unloading (up to 18%) [127] Strong distribution of pores produced by the L-PBF sample [127,128] Additional re-melting led to smaller grain size and yielded a deformability of 14% [129] Higher strength and improved plasticity was observed for both samples (Cu-Al-Ni-Mn and Cu-Al-Ni-Mn-Zr) [128][129][130] For the Cu-Al-Ni-Mn-Zr sample, Zr-rich phase was found to precipitate at the grain boundaries during the annealing process [130] Cu-Al-Ni-Mn-Zr Cu-Al-Ni-Ti Copper alloy with Ti addition had a high hardness of about 280 HV due to the grain refinement.…”

Application of fuzzy AHP – TOPSIS for ranking additive manufacturing processes for microfabrication

“…These implants can be manufactured with laser-based process such as SLS, but implants that resemble bones have micro and macro voids. Hence, feature size of microscale is needed which can be fabricated with micro laser sintering process that uses laser beam of small diameter (Khademzadeh et al , 2015). Two-photon polymerization-based microstrereolithography finds its application in optical devices and fabrication of other microstructures because of its unique advantages such as almost any complex profile can be reproduced, resolution of the printed part can reach up to sub-micron level.…”

Thermal History Mapping in Powder Bed Laser Sintering at the Micrometer Scale

“…This process depends on the thermal characteristics of the material and on a set of parameters of the device . Focal length is one of these laser parameters to control the ceramic or metal sintering. − The main effect of defocusing is to reduce the reached temperatures . Also, defocusing leads to an increase in the spot diameter, resulting in a higher sintering homogenization near the beam spot.…”