What are the advantages and disadvantages of laser texturing compared to other texturing processes in forming tool surface?4 answersLaser surface texturing (LST) offers several advantages compared to other texturing processes in forming tool surfaces. LST allows for controllable surface structuring and the acquisition of specific physical surface properties needed in functional surfaces. It provides a non-contact method for fabricating functional surfaces, improving wettability, and enabling extreme wetting. LST is compatible with various materials and can result in a hierarchical texture. Additionally, LST allows for the creation of surface structures and surface chemical modifications that enhance wettability. However, there are some limitations to LST. The quality and processing rate of LST depend on the correct choice of a scanning strategy. Furthermore, the high purchase prices of laser technology have been an obstacle to its widespread use, especially for cutting applications.
What is the mechanism by which laser remelting affects the microstructure distribution and tribological properties of 65Mn steel?4 answersLaser remelting affects the microstructure distribution and tribological properties of 65Mn steel through several mechanisms. The peak temperature during laser treatment affects the microstructure, with the martensitic microstructure being coarser near the outer surface of the hardened layer due to higher temperatures. The peak temperature decreases exponentially with increasing depth and increases linearly with laser power and scanning rate. Laser remelting also improves the wear resistance of the steel by producing a denser and finer microstructure in the remelted composite coating, reducing the average grain size and increasing the microhardness. The wear resistance is further improved by the presence of hard phases such as BCC and Mx(B, Si) and the proper proportion of these phases in the coating. Additionally, laser remelting promotes the formation of anti-wear barriers, such as the CrC phase, which enhances the tribological performance of the steel.
How does the aspect ratio of dimples affect wear and friction in laser-textured surfaces?5 answersThe aspect ratio of dimples has a significant effect on wear and friction in laser-textured surfaces. The depth of the dimple is found to be the main factor influencing the friction and wear properties of the surface. Surfaces textured with a depth of 10 μm have been shown to have the best properties, with a significant reduction in friction and wear. Additionally, the wear rates of worn ceramic balls and the friction coefficient can be reduced by using textured surfaces with solid lubricants. The size of the dimples also plays a role, as laser-textured samples with smaller dimples (5 μm) exhibit improved tribological properties compared to non-textured samples. The tribological characteristics of the frictional interaction pairs can be improved by controlling the area density ratio of the dimple-texture pattern. Overall, the aspect ratio of dimples, including the depth and size, is crucial in determining the wear and friction properties of laser-textured surfaces.
How can coating and texturing be used to improve tribological properties?5 answersCoating and texturing can be used to improve tribological properties. Surface coating involves depositing a thin layer of suitable material on the surface to enhance friction and wear characteristics. Surface texturing, on the other hand, involves creating micropatterns on the contacting surfaces. By using these techniques, the wear resistance of compression piston rings in internal combustion engines can be improved. Laser-texturing thin coatings on stainless steel substrates can reduce the hardness of the coatings and prevent tearing, leading to improved wear life. Surface texturing methods such as scraping or ultrasonic vibration-assisted turning (UVAT) can create small depressions on the surface, which function as oil holes and improve lubrication performance. These techniques can also optimize the tribological characteristics of medical devices without compromising their design features and functionality.
Does the laser texturing on SS321 induce changes in the surface wettability?5 answersLaser texturing can induce changes in the surface wettability of stainless steel (SS321). Laser surface treatment can alter the surface chemistry and characteristics of the steel, which can affect the wettability. Laser surface texturing is a non-contact manufacturing process that can improve wettability and is widely used in various industries. The construction of a reasonable texture can enhance surface hydrophilicity, leading to the formation of a lubricating film and reducing abrasive and adhesive wear. Laser-assisted texturing of surfaces can modify the wettability behavior of materials, and different patterns can result in hydrophobic surfaces with varying contact angles. Controllable surface wettability can be achieved through laser-thermal hybrid processing, and the wettability difference can be regulated by heat treatment temperature. Therefore, laser texturing can indeed induce changes in the surface wettability of stainless steel, providing opportunities for various industrial applications.
What are the tribological properties of the new material?2 answersThe tribological properties of the new materials investigated in the provided abstracts vary. The sintered steel materials coated with DLC showed increased resilience to wear and resistance to contact fatigue. The combination of multilayer graphene (MLG) and WS2 exhibited excellent tribological properties, with a continuous lubricating film reducing friction coefficient and wear rate. The Fe3Al material sliding against Si3N4 ceramic ball showed a wear rate in the orders of 10^-4 mm^3 m^-1, with increasing load and sliding speed leading to a transformation in the wear mechanism. Carbon-rich metal/carbon coatings of chromium, tungsten, and titanium showed a strong dependence on composition for their tribological properties, with the three-body wear resistance of tungsten carbon compounds correlating with Vickers hardness.