On Defect Minimization Caused by Oxide Phase Formation in Laser Powder Bed Fusion

Abstract

The article is devoted to the compressive review of the defects observed in the products of the machinery usage made mainly of anti-corrosion steels of the martensite-austenite group, difficult to process materials such as pure titanium, nickel, and their alloys, super and high entropy alloys and triple fusions produced by laser additive manufacturing, particularly the laser powder bed fusion. Studies were conducted on the structural defects observed in such products to improve their quality in the context of residual stress elimination, porosity reduction, and surface roughness improvement. Electrophysical and electrochemical treatment methods of removing oxide phase formation during melting and remelting of deposed tracks in layers are considered (such as ultrasound, plasma, laser, spark treatment, induction cleaning, redox annealing, gas–flame, plasma–beam, plasma–spark treatment). Types of pollution (physical and chemical) and cleaning methods, particularly plasma-based methods for oxide phase removing, are classified. A compressive comparison of low- and high-pressure plasma sources is provided. Special attention is focused on the atmospheric plasma sources based on a dielectric barrier and other discharges as a part of a production setup that presents the critical value of the conducted review in the context of the novelty for transition to the sixth technology paradigm associated with the Kondratieff’s waves.

Simulation of Mechanical and Thermal Loads and Microtexturing of Ceramic Cutting Inserts in Turning a Nickel-Based Alloy

“…• the presence of microcracks due to the shrinkage of the molten material as it solidifies [22,23]; • the presence of surface morphology subjected to repeated focal overheating with the creation of near-track/weld stress zones (heat-affected zones) [24,25]; • active evaporation of the lightest materials from the processing zone [26,27]; • formation of a transitional nanoporous interlayer consisting of more refractory material components [28,29]; • increased formation of brittle structures in the near-surface layer (the formation of second-order secondary compounds on the heating surface, due to the material's active oxidation as a result of the interaction of the molten material of the cutting insert/substrate and coating with the environment) [30]; • splashing of material from the processing zone due to thermal shock [31,32].…”

Advances in Laser Materials Processing

“…The post-processing (mechanical, heat and plasma treatment) of laser welds and parts produced by laser additive manufacturing [17][18][19].…”

“…These subjects can be highlighted as the main, crucial research directions in laser materials processing. The topics of the laser surface treatment of cast irons [16] and defect minimization in the laser powder bed fusion of metals and alloys [19] are reviewed.…”

“…The roughness parameter Ra was reduced by 4.2 times for the X20Cr13 sample after cavitationabrasive finishing when the roughness parameter Ra for the X10CrNiTi18-10 sample was reduced by 2.8 times after vibratory tumbling. The compressive review [19] observes the defects in the additively manufactured machinery products of the anticorrosion steels of the martensite and austenite classes; difficult to process materials such as pure titanium, nickel, and their alloys; super and high entropy alloys; and triple fusions. Studies were conducted on the structural defects observed in such products to improve their quality by eliminating residual stress, reducing porosity, and improving surface roughness.…”