Laser cladding induces high tensile residual stress (RS), which can compromise the quality of a specimen. Therefore, it is critical to accurately predict the RS distribution in cladding and understand its formation mechanism. In this study, functionally graded material (FGM) layers were successfully deposited on the surface of a titanium alloy Ti6Al4V sheet by laser cladding technology. A corresponding thermo-mechanical coupling simulation model of the laser cladding process was developed to investigate the formation mechanism of RS in the laser cladding FGM layers. The results show that high tensile RS forms in cladding components. Subsequent cladding can effectively alleviate the RS in cladding components although the position of maximum RS remains unchanged. The measurement results of the longitudinal RS on the top and bottom surfaces of cladding components by the X-ray diffraction (XRD) method agreed with the simulation results, thereby proving the accuracy of the simulation. In addition, the formation mechanism of RS in the laser cladding FGM layers was revealed by discussing the individual impact of each material property on RS. It was indicated that the RS distribution in the laser cladding FGM layers was significantly affected by material properties (in particular, coefficient of thermal expansion and Young’s modulus), except for the temperature gradient induced by the laser cladding process.

Impacts of laser cladding residual stress and material properties of functionally graded layers on titanium alloy sheet

Effect of weld reinforcement on tensile and fatigue properties of 5083 aluminum metal inert gas (MIG) welded joint: Experiments and numerical simulations

An extruded profile of Al-Mg-Si alloy was metal-inert-gas-welded (MIG-welded) with an ER5356 filler wire and the microstructures, mechanical properties and fatigue behavior of the joints were investigated. Compared with the base material (BM), coarser grains are present in the heat-affected zone (HAZ) as a result of abnormal growth in the welding process. The average grain sizes of the weld zone (WZ) and BM were 40.8 µm and 16.8 µm, respectively. The ultimate tensile strength (UTS) of the MIG-welded joint and BM were 210.3 MPa and 274.8 MPa, respectively, thus, the weld joint efficiency was approximately 76.5%. Fracture appeared at the location with the minimum hardness in the HAZ of the MIG-welded joint during tensile tests. Based on the fatigue testing experiment with 107 cycles, the conditional fatigue strengths of the MIG-welded joint and BM were 61.7 MPa and 141.3 MPa, respectively. Welding defects, such as coarse secondary phase, welding pores and incomplete fusion, caused local stress concentration which initiated fatigue crack and apparently increased the fatigue crack growth rate of the MIG-welded joint, ultimately causing the premature fracture of the joint at the WZ.

Microstructures and fatigue behavior of metal-inert-gas-welded joints for extruded Al-Mg-Si alloy

Influence of multi-beam preheating temperature and stress on the buckling distortion in electron beam welding

Nucleation and evolution of β phase and corresponding intergranular corrosion transition at 100–230 °C in 5083 alloy containing Er and Zr

Mitigating distortion and residual stress by static thermal tensioning to improve fatigue crack growth performance of MIG AA5083 welds

The trend in mechanical design and manufacturing process is marked by the use of thin structures to reduce product weight and fuel savings. It is known that the main problem related to the welding of thin plates is distortion and residual stress which influence fatigue performance of welded structures. The aim of this study is to minimize distortion, improve the mechanical properties and to increase fatigue crack growth resistance of flux-cored arc A 36 steel welded joints using static thermal tensioning (STT) process. In this research, FCAW welding was conducted with and without STT process. The voltage, current, and heat input were 40 Volt, 210 Ampere and 2.184 kJ/mm, respectively. The position of both heaters was 80 mm, and weld with the cooling system was heated near weld center line. During the experiment, the weld metal cycles were measured using data acquisition. After completing the welding process, a sequence of the experiment was conducted including chemical analysis, measurement of distortion, ...

/pdf/the-effect-of-heating-temperature-in-static-thermal-1dsdhzdxlf.pdf

The effect of heating temperature in static thermal tensioning (STT) welding on mechanical properties and fatigue crack propagation rate of FCAW in steel A 36

This study investigates the effects of fiber treatments on mechanical properties of pineapple leaf fiber reinforced polyester composites (PALF/PE). The Fiber treatments were conducted with 3%, 6% and 9% NaOH for 2 hours. The untreated and treated PALF/PE composites were fabricated by the vacuum infusion method. The result analysis revealed that PALF/PE composites treated with NaOH indicated an increasing pattern in mechanical properties compared to untreated PALF/PE composites. The highest tensile strength was112 Mpa at 6 % NaOH and the highest impact strength was 0.11891 Joule/mm2 at 6 % NaOH. Moreover, the fracture images indicate relatively less fiber pull-out and improved fiber/matrix adhesion. The composites would be promising for construction, furniture and automotive materials due to their superior mechanical properties. 

https://aip.scitation.org/doi/pdf/10.1063/5.0094474

Effect of alkali treatment on mechanical properties of pineapple leaf fiber/polyester composites by vacuum infusion method

The high demand for electrical energy leads to the depletion of fossil fuel reserves. Therefore, alternative energy is required to overcome the scarcity of fossil fuels. Regardless of the fact that natural resources are renewable as alternative energy such as wind, water, ocean waves, and sunlight. Wind on the south coast of Malang, Indonesia provides good potential as alternative energy. The design in this paper is focused on designing a horizontal axis wind turbine with 4 blades with a length of 50 cm utilizing the NACA 4412 Airfoil profile. The wind turbine is designed utilizing a low-speed permanent magnet generator around 500-1000 rpm to produce a design power of 100-125 Watt and the maximum power of the generator of 270 Watt. The wind turbine that has been designed has a tower-shaped support that uses iron pipes and is pulled by 4 steel ropes that are plugged in each pointing to the 4 cardinal directions. 

Design of a micro-scale wind turbine with horizontal axis using airfoil NACA 4412

This study aims to discover the best flame temperature in the Transient Flame Static Tensioning method. The used flame temperatures in this study are 100°C, 200°C and 300°C. The minimum distortion is performed by utilizing a flame temperature of 200°C, 300°C and 100°C. The tensile strength in the flame temperature variation of 100°C, 200°C, and 300°C is 231.197 Mpa, 169,658 Mpa, and 156.729 Mpa respectively. The highest hardness of the base metal is at a flame temperature specimen of 100°C with a value of 10.1321 kg/mm2. The highest hardness in the HAZ area is at a flame temperature variation of 300°C with a value of 15.9812 kg/mm2. The highest hardness of the welding metal area is at a flame temperature variation of 300°C with a value of 12.5805 kg/mm2. Thus, 200°C provides the ideal temperature for welding. The temperature distribution in this study indicates that higher heat input affects higher temperature around the welding area and vice versa. The provision of static cooling is to reduce the peak temperature around the welding despite insignificant results. 

N. Subeki

Papers

Mitigating distortion and residual stress by static thermal tensioning to improve fatigue crack growth performance of MIG AA5083 welds

The effect of heating temperature in static thermal tensioning (STT) welding on mechanical properties and fatigue crack propagation rate of FCAW in steel A 36

Effect of alkali treatment on mechanical properties of pineapple leaf fiber/polyester composites by vacuum infusion method

Design of a micro-scale wind turbine with horizontal axis using airfoil NACA 4412

Effect of transient flame static tensioning method on distortion and mechanical properties of aluminum A5083 with MIG welding