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Laser Heat Treatment of Ferrocarbon Powder Steel
摘要： The laser heat treatment of sintered ZhGr ferrocarbon powder steel with different porosity is considered. The microstructure and microhardness of the steel are determined, and the defects arising in laser treatment are studied.
关键词： microhardness,ferrocarbon steel,porosity,laser heat treatment,powder metallurgy,microstructure
更新于2025-09-23 15:19:57
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Laser hardening of copper-iron pseudoalloy
摘要： The purpose of the study is to improve the performance characteristics of powder pseudo-alloy materials using surface heat treatment. Such materials have unique properties, for example, self-lubrication under dry friction conditions, high thermal conductivity coefficient, and high electro-erosion resistance. The disadvantage of powder pseudo-alloys is their relatively low strength. The paper considers the method of surface hardening by high-energy treatment - laser radiation. The paper describes the method of experimental research, describes the method of obtaining powder material, its chemical composition, shows the equipment used. The results of studies of the microstructure and microhardness of the surface layer of steel-copper powder pseudo-alloy after laser heat treatment (LHT) of a continuous-wave fiber laser with a maximum power of 1 kW are given, LHT modes are indicated, the influence of LHT parameters on the characteristics of the hardened layer is evaluated. It is revealed that the partial melting region in which melting occurs in the volumes of the fusible component (copper) in the initial structure and contacting segments of steel matrix is formed in the material in addition to the total melting zone. Then the quenching zone from the solid state follows, in which the maximal hardness up to 1000 HV is attained for best samples in the volume of martensite, which is formed in perlite colonies of the initial steel–copper material.
关键词： Steel–copper pseudoalloy,Microhardness,Abrasive wear,Laser heat treatment,Powder metallurgy,Microstructure
更新于2025-09-23 15:19:57
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POST WELD HEAT TREATMENT OF NiTinol SHAPE MEMORY ALLOY USING LASER POWER SOURCE
摘要： In this work, attempt is made to carry out post weld heat treatment (PWHT) on NiTinol samples using laser power source. Initially, 1 mm thick NiTinol sheets were welded in butt joint position using Ytterbium: Yttrium aluminum garnet (Yb: YAG) laser power source. Laser welding was carried out in continuous mode, and the quality of the weld was assessed with respect to phase transformation temperatures, microhardness, tensile strength, and corrosion resistance. To improve the quality of the welded samples, PWHT was done by passing a laser beam over the welded samples. It was found that PWHT had a significant effect on the phase transformation temperatures, microhardness, tensile strength and corrosion behavior of the welded NiTinol joints.
关键词： laser heat treatment,NiTinol,laser welding,mechanical properties,corrosion behavior
更新于2025-09-19 17:13:59
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Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves
摘要： The structures in high-temperature environments are prone to undergo hardening and embrittlement as a result of thermal aging; this can cause variations in their mechanical properties. Because these changes occur at the microstructural level, it is difficult to evaluate them through linear ultrasonic techniques. In this work, a surface acoustic wave (SAW) was used to measure and compare the acoustic nonlinearity and mechanical properties of Al6061 alloys heat-treated at 220°C for different durations (0 min, 20 min, 40 min, 1 h, 2 h, 10 h, 100 h, 1000 h). The SAW was generated by a pulsed laser and then received by an interferometer. Moreover, the yield strength, ultimate strength, and elongation to failure were measured by tensile tests. The results demonstrate that the critical variations in the mechanical properties can be detected by monitoring the variation features in the acoustic nonlinearity. Transmission electron microscopy images were captured to observe the microstructural changes, which shows that the acoustic nonlinearity varied according to the change in the precipitation phase. This supports the acoustic nonlinearity measurement using the laser-generated SAW being an effective technique for the fully noncontact nondestructive evaluation of material degradations as well as changes in mechanical properties.
关键词： surface acoustic wave,material degradation,laser,heat treatment,mechanical property,thermal aging,nonlinear parameter,precipitation,acoustic nonlinearity
更新于2025-09-19 17:13:59
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Hybrid Process of Laser Heat Treatment and Forming of Thin Plate with a Small Power Semiconductor Laser
摘要： In recent years, the recycling of resources has become important because of the aggravation of global environmental concerns. In light of this, it is necessary to minimize the resource needs of current production systems. This concept is called sustainable development. When this concept is applied to machine tools, the assumption is that small parts should be processed using small machines. Additionally, the diversification of consumer needs and the ephemeralization of product life cycles are progressing in industry. As a result, the overall production system has changed from high-mix low-volume production manufacturing, to variant types in variable quantity. In this background, the cell production system is receiving attention as a production system that can achieve variant types in variable quantity. The cell production system also requires miniaturization and process consolidation of machine tools, which has given rise to the need to consolidate heat treatments, especially as part of the process consolidation of machine tools. Laser beams have proved to be effective heat sources when integrated into heat-treatment processes, such as quenching and tempering on machine tool tables. On the other hand, In the case of the thin plate, it is well known that the deformation of a plate occurs due to laser irradiation, as named a laser forming. The laser forming is also effective to generate the complex shape without a press die set. Thus, we propose that the hybrid process of laser heat treatment and forming of thin plate with a small power semiconductor laser, and demonstrate that the proposed method makes it feasible to generate the hardened sheet metal products with a compact machine tools. Moreover, considering the power consumption in laser quenching and forming process, we investigate an appropriate laser irradiation condition from a view of reducing the environmental burden.
关键词： Laser forming,Compact machine tools,Sustainable manufacturing,Laser heat treatment,Small power semiconductor laser
更新于2025-09-16 10:30:52