Effect of the Laser Surface Treatment on Properties of the Alloy (Ni-Cu-V) Nanoparticles Prepared by Powder Metallurgy Method

In this research, an alloy with a nanostructure was prepared using a metallurgical technique. To prepare an ideal alloy, three nanoscale powders were used (70 percent Ni, 25 percent Cu, and 5 percent V). The dried alloy was stored under 8 Tons of cold pressing at 80°C for 30 minutes. After that, a surface treatment of the prepared alloys with different laser energies (0, 200, 260, 300) mJ was carried out with a pulse time (10 seconds) at a distance of (100 cm). and hardness (Rockwell method) is studied. By immersing samples in a solution (3.5 percent NaCl) for different periods (3, 5, 7, 9, 11) days, the effect of laser surface treatment on the corrosion resistance of the alloy was investigated. Results show that porosity, water absorption ratio decreases after laser surface treatment with rising hardness values. Additionally, the wear resistance decreases as laser energy increases. Atomic force microscope images show that grain sizes increase as laser energy increases, and by increasing the laser energy, the surface of the nanoparticles is more homogeneous. Easy architecture and high nanostructure alloy consistency play a key role in improving the mechanical and physical properties.

Effect of laser-induced ultrasound treatment on material structure in laser surface treatment for selective laser melting applications

A new mechanism for controlling the microstructure of products in manufacturing processes based on selective laser melting is proposed. The mechanism relies on generation of high-intensity ultrasonic waves in the melt pool by complex intensity-modulated laser irradiation. The experimental study and numerical modeling suggest that this control mechanism is technically feasible and can be effectively integrated into the design of modern selective laser melting machines.

A comparative study on surface topography and micro hardness of laser polished hardened AISI D2 tool steel

In this work, a laser polishing-hardening (LPH) method with integration and high efficiency for the treatment of AISI D2 tool steel was proposed, and the effects of laser hardening (LH), laser polishing (LP) and LPH treatments on the surface topography and microhardness were examined. The results show that LH method had a negligible effect on the surface roughness of the treated sample, while the surface roughness Ra of LP and LPH specimens was reduced by 74.6% and 80.9% respectively, indicating that the milled surface topography had been significantly improved, especially LPH was more effective in reducing the roughness. Besides, the polishing efficiency of LPH was 10 times that of LP approach. In terms of hardness improvement, the near-surface microhardness of LH and LPH samples increased by 1.5 times and 1.3 times respectively, and the effective hardened zone (EHZ) depth was 0.42 mm and 0.24 mm respectively, demonstrating that these two laser processing methods had a beneficial effect on the cross-section microhardness of D2 tool steel, while the increase of LP on the microhardness was insignificant. The comprehensive analysis of the surface morphology and microhardness of LPH specimen indicates that LPH was a feasible laser surface treatment method for D2 tool steel. On the premise of ensuring a high surface finish, the polishing efficiency can be remarkably improved, the subsurface microhardness and EHZ depth of processed specimen can be also significantly enhanced, which provided a feasible idea for the application of laser surface treatment technology in industrial mold production.

Tailoring Al–Li Alloy Surface Wettability with a Femtosecond Laser and Its Effect on Bonding Performance

In this study, a femtosecond laser was used to pretreat the surface of the Al–Li alloy, the surface micromorphology, roughness, contact angle, and surface wettability of which were adjusted by changing the laser scanning speed, and the sample was bonded into a single joint with polyether ether ketone (PEEK) adhesive. The mechanism of the laser surface treatment affecting the bonding strength of the Al–Li alloy was explored through tensile and shear experiments. The results indicated that optimizing the laser surface treatment parameters could change the surface roughness and surface micromorphology of the Al–Li alloy, so as to change its surface free energy and bonding strength. Compared with the untreated sample, the bonding strength of the Al–Li alloy increased by 81%, 95%, 107%, 91%, and 78% under the treatment of laser scanning at 25, 20, 15, 10, and 5 mm/s, respectively. As a whole, femtosecond laser etching of the Al–Li alloy surface had an important influence on its wettability and bonding performance.