Surface Microprocessing AISI-O1 by Pulsed Nd: YAG Laser

Due to tedious and time-consuming work put into the conventional mold/die microprocessing (about 37% of the total time of the entire mold/die production). Therefore, to improve or enhance the quality of mold/dies at the final step with a less number of trained and skilled operators or decrease the processing time to cut the overall cost dramatically, AISI-O1 cold work steel was micro-processed by Pulsed Nd: YAG laser. The influence of laser processing parameters on the evolution of the correlated surface morphology was investigated by a 3D profilometer, scanning electron microscopy (SEM), and optical microscopy (OM). The results show that when AISI-O1 specimens were irradiated with various parameters, the morphology of AISI-O1 cold work steel was changed correspondingly. It also demonstrates that the different kinds of micro-processed surface morphology could be established successfully to satisfy the later practical requirements for a given laser. Meanwhile, the effect of laser processing parameters on the relevant temperature was described, and the laser microprocessing temperature field was also proposed. It reveals that the influence of laser pulse feed rate was more prominent than that of other parameters on the relevant micro-processed surface morphology

Fracture Variation of Welded Joints at Various Temperatures in Liquid-Phase-Pulse-Impact Diffusion Welding of Particle Reinforcement Aluminum Matrix Composites

The fracture variation of liquid-phase-pulse-impact diffusion welding (LPPIDW) welded joints of aluminum matrix composites (ACMs: SiCp/A356, SiCp/6061Al, and Al2O3p/6061Al) was investigated. Results show that under the effect of pulse-impact (i) initial pernicious contact state of reinforcement particles changes from reinforcement (SiC, Al2O3)/reinforcement (SiC, Al2O3) to reinforcement (SiC, Al2O3)/matrix/reinforcement (SiC, Al2O3) and (ii) the fracture of welded joints with optimal processing parameters is the dimple fracture. Meanwhile, scanning electron microscope (SEM) of the fracture surface shows some reinforcement particles (SiC, Al2O3) in the dimples. Moreover, the slight reaction occurs at the interfaces of SiCp/6061Al, which is propitious to improve the property of welded joints because of the release of internal stress caused by the hetero-matches between the reinforcements and matrix. Consequently, aluminum matrix composites (SiCp/A356, SiCp/6061Al, and Al2O3p/6061Al) were welded successfully

Carbon Nanotubes Coating for Micropunch

The multi-walled carbon nanotubes (MWCNTs) were coated on micropunch homemade equipment with the waste alcohol as a resource. The correlated characteristics were evaluated by scanning electron microscopy (SEM), transmission electron microscope (TEM), and Raman spectroscopy. Moreover, the synthesized MWCNTs were grown on some micropunches to confirm the relevant, beneficial effect on the service life of micropunches compellingly and convincingly. The results indicate that MWCNTs coated on micropunch can enhance its service life up to 35% of that without MWCNTs. Due to the lubrication of MWCNTs coating between the micropunch and the specimen, the wear of the micropunch coated with MWCNTs distinctively decreases, even in the severe wear period. As a result, the correlated wear loss is also less than that of the micropunch without MWCNTs coating, ascribed to the graphitic nature of MWCNTs. Meanwhile, because of the usage of the waste alcohol, the technique of the relevant synthesized MWCNTs is green to the environment, which is promising for practical applications

Effect of Milling Time on Surface Morphology of AISI O1

Abstract: AISI O1 was processed by surface milling and the influence of milling time on the surface morphology was studied by 3D profilometer and scanning electron microscopy (SEM). Results show that when AISI O1 specimens are processed with various milling time, the morphology of AISI O1 changes correspondingly. Moreover, it demonstrates that the initial increase in milling time accompanies with the increase in surface roughness until the milling time reaches 60 min at which the surface roughness is the minimum

Simulation of Micro-Precoating Effect on Temperature Distribution in Plasma Thermal Spraying

Abstract: The effect of micro-precoating on temperature distribution of the plasma thermal spraying was simulated. After the plasma thermal spraying test with SS304 as precoating, the effect of micro-precoating on the wear loss and fatigue had been studied preliminarily. Results show that the surface temperature with micro-precoating is higher than that of without micro-precoating. Meanwhile, the heat affected zone with precoating is wider which effectively restrains the microcracks forming in the succedent coating. Subsequently, the wear and fatigue of the plasma thermal spray coating are significantly increased with the optimum micro-precoating thickness

Morphology Evolution of DF2 (AISI-O1) Surface Micromachined by Pulsed Nd:YAG Laser

Pulsed Nd:YAG laser was taken to premicromachine DF2 (AISI-O1) cold work steel. The effect of laser-irradiated parameters on the morphology evolution of the processed surface was investigated by 3D profilometer, atomic force microscope (AFM), scanning electron microscopy (SEM), and optical microscopy (OM). Results show that when DF2 (AISI-O1) specimens were irradiated with various parameters, the morphology of DF2 (AISI-O1) cold work steel was changed correspondingly. Moreover, it demonstrates that for a given laser, various kinds of morphology of a laser-machined surface could be established successfully to satisfy with the desired finish surface for the practical applications later

Influence of Al₂O₃ Processing on the Microtexture and Morphology of Mold Steel: Hydrophilic-to-Hydrophobic Transition

The surface of mold steel was processed by the simple Al2O3 surface processing, and the influence of processing time on the surface morphology was studied by 3D profilometer and scanning electron microscopy (SEM). Moreover, the wettability of the Al2O3 microtextured surfaces of mold steel was also investigated. The results show that the surface morphology of mold steel varies with Al2O3 processing time. It reveals that the initial surface without any Al2O3 processing treatment behaves as a hydrophilic surface. With the increment of Al2O3 processing time, the surface roughness of the processed surface with the microtextures increases correspondingly. At the same time, the wettability of the microtextured surfaces changes from the hydrophilic to the hydrophobic. When Al2O3 processing time reaches 60 min, the contact angle reaches its maximum at which the relevant surface roughness is the minimum. It indicates that mold steel with an Al2O3 microtextured surface can be a potential application in the mold releasement