Microstructure evolution and mechanical properties of 6N01S-T5 aluminum alloy joints with semi-solid solders by ultrasonic soldering

The article investigated the properties of 6N01 aluminum alloy joints with Sn-80Zn semi-solid solders by ultrasonic soldering. It was found that semi-solid solders consisted of Zn-rich phase with short rod-like dentrite, which had the lower solidus temperatures, while Zn-rich phase with long dentritic grains used the conventional solders. The joints soldered with Sn-80Zn conventional filler metal reached maximum shear strength of 73 MPa at the soldering temperature of 390[Formula: see text]C. The joint using Sn-80Zn semi-solid solder obtained higher shear strength of 90 MPa at the lower temperature of 370[Formula: see text]C. The effects of the ultrasonic time and the soldering temperature on the mechanical properties of the joints were also investigated with the Sn-80Zn semi-solid solders.

The 6N01 Aluminum Components by Orthogonal Design Optimization

In this study, we designed four components of 6N01 aluminum alloy by orthogonal design, and analyzed the effect of the different elements for the mechanical properties and microstructure of the designed material after casting, homogenization annealing, extrusion treatment and natural aging. Considering the above series of tests of the data indicators, and thus orthogonal filter out two materials that all aspects of performance are more excellent.Keywords: orthogonal design; 6N01 aluminum alloy; mechanical properties; microstructure

Evaluation of the Fatigue Life in Aluminum Alloy Welded Joint by Nonlinear Ultrasonic Testing

Fatigue is a common phenomenon in welded structures. Prediction of fatigue life of welded joints in-service is still an unsolved puzzle by the conventional linear ultrasonic testing method. However, the nonlinear ultrasonic waves or the acoustic nonlinear signal can provide clear signs of the accumulative fatigue damage in materials, as reported by a number of researchers. Hence, the nonlinear ultrasonic testing method has revealed a tremendous potential for fatigue damage evaluation. This paper presents a study to characterize the fatigue damage using the analysis of the signal characteristics and a new nonlinear parameter. Based on the very high-cycle fatigue testing results for a 6N01 aluminum alloy welded joint, the relationship between the amplitude of the second-order harmonic and fatigue cycling has been established. The nonlinear ultrasonic system test results show that the amplitude of the second-order harmonic increases at the early fatigue stage, with further increase in cyclic loading until reaching a peak. Metallographic examinations show that a fatigue crack will nucleate in the weld joint in the stage as the amplitude reaches the peak value. Finally, theoretical and experimental results confirm that the amplitude of the second-order harmonic is useful for assessing the fatigue life of a 6N01 aluminum alloy welded joint.