激光功率对Nd:YAG激光焊接钛管材料的显微组织和力学性能的影响

采用Nd:YAG激光束焊接连接2级钛管。通过组织表征和力学试验研究了激光功率的影响。结果表明,随着激光功率的增加,焊珠的几何形状从楔形变成了平行形,焊接区呈粗糙、不均匀、锯齿状的粗颗粒结构。激光功率对晶粒的位向角分布也有显著影响。高功率激光导致焊接区出现了较大的孔隙,还有高密度的位错和亚晶界。通过激光焊接,材料的强度得到提高,但通过显微硬度分析发现,高功率激光下材料的强度提高较小,而在较低功率的激光下,材料可以获得更高的抗拉强度。通过断口分析发现,焊接区存在的微小空隙导致材料出现韧性断裂。

Prediction and optimization of process parameter of friction stir welded AA5083-H111 aluminum alloy using response surface methodology

A systematic approach was presented to develop the empirical model for predicting the ultimate tensile strength of AA5083-H111 aluminum alloy which is widely used in ship building industry by incorporating friction stir welding(FSW) process parameters such as tool rotational speed,welding speed,and axial force.FSW was carried out considering three-factor five-level central composite rotatable design with full replications technique.Response surface methodology(RSM) was applied to developing linear regression model for establishing the relationship between the FSW process parameters and ultimate tensile strength.Analysis of variance(ANOVA) technique was used to check the adequacy of the developed model.The FSW process parameters were also optimized using response surface methodology(RSM) to maximize the ultimate tensile strength.The joint welded at a tool rotational speed of 1 000 r/min,a welding speed of 69 mm/min and an axial force of 1.33 t exhibits higher tensile strength compared with other joints.

Optimization of process parameters to maximize ultimate tensile strength of friction stir welded dissimilar aluminum alloys using response surface methodology

Aluminium alloys generally present low weldability by traditional fusion welding process.Development of the friction stir welding(FSW)has provided an alternative improved way of producing aluminium joints in a faster and reliable manner.The quality of a weld joint is stalwartly influenced by process parameter used during welding.An approach to develop a mathematical model was studied for predicting and optimizing the process parameters of dissimilar aluminum alloy(AA6351 T6 AA5083 H111)joints by incorporating the FSW process parameters such as tool pin profile,tool rotational speed welding speed and axial force.The effects of the FSW process parameters on the ultimate tensile strength(UTS)of friction welded dissimilar joints were discussed.Optimization was carried out to maximize the UTS using response surface methodology(RSM)and the identified optimum FSW welding parameters were reported.

Synthesize of AZ31/TiC magnesium matrix composites using friction stir processing

Friction stir processing(FSP)is a novel solid state technique to synthesize metal matrix composites.In the present work,an attempt has been made to synthesize AZ31/TiC magnesium matrix composites using FSP and to analyze the microstructure using scanning electron microscopy.A groove was prepared on 6 mm thick AZ31 magnesium alloy plates and compacted with TiC particles.The width of the groove was varied to result in four different volume fraction of TiC particles(0,6,12 and 18 vol.%).A single pass FSP was carried out using a tool rotational speed of 1200 rpm,traverse speed of 40 mm/min and an axial force of 10 kN.Scanning electron microscopy was employed to study the microstructure of the synthesized composites.The results indicated that TiC particles were distributed uniformly in the magnesium matrix without the formation of clusters.There was no interfacial reaction between the magnesium matrix and the TiC particle.TiC particles were properly bonded to the magnesium matrix.

异种搅拌摩擦焊AA5083-H111和AA6351-T6铝合金的力学和冶金性能(英文)

研究异种搅拌摩擦焊AA5083-H111和AA6351-T6铝合金的微观结构和力学性能。在3种不同的焊接速度(36、63、90 mm/min)下焊接AA5083-H111和AA6351-T6铝合金,分析焊接速度对接头力学和冶金性能的影响。结构表明,与其他焊接速度相比,焊接速度为63 mm/min时接头的力学性能和冶金性能较好。焊缝区由未混合区、机械混合区和混流区组成。所观察到的断裂模式为韧性纤维断裂。