DP780 steels and 6061‐T6 aluminum alloys are joined using the resistance element welding (REW) process with a flat Q235 rivet. The macrostructure, microstructure, and mechanical properties of the REW joints are investigated. The nugget zone and upper‐critical heat‐affected zone (UGHAZ) microstructure exhibit lath martensite. The inter‐critical heat‐affected zone (ICHAZ) microstructure consists of ferrite and martensite. Two types of intermetallic compound (IMC) layers are formed at the steel/Al interface. A tongue‐like Fe2Al5 layer is found adjacent to the steel side, while a needle‐like Fe4Al13 layer is found adjacent to the aluminum alloy side. The welding current has a significant influence on the nugget size, peak load, and energy absorption of joints. The fracture behavior analysis of the REW joints is performed using the in situ digital image correlation (DIC) method. There are two failure modes of the REW joint under different welding currents: pull‐out failure (POF) and the base material pull‐out failure (BPF). At a welding current of 17 kA, the maximum tensile‐shear value of the REW joints is 6.27 kN with a nugget diameter of 5.37 mm. The failure mode of the REW joints is mainly BPF mode that exhibits superior lap‐shear performance.
In this paper, we introduce the Dirac equation and the hole theory of antiparticle generation, and the history of antiparticle discover. We study of the physical properties of the antiparticles; we point out that antigravity does not exist. We introduce the ideas of two talented physicists and Cabibbo theory which have important influence on the research of origin of the matter–antimatter asymmetry, we propose that the “Dirac energy sea” is compatible with Feynman’s idea that antiparticles are “time reversals” of particles and be used to analyze some cosmological problems. In this paper, we review and analyze a lot of literatures about the asymmetry research on matter and antimatter generation, the available data from astronomical observations, and we can conclude that: everything around us within [Formula: see text] light-years is made of matter the present-day observable universe most likely does not contain significant amounts of antimatter. We provide extensive analysis and introduce observation of antimatter from space, review massive literature on related research, it shows that the present theory cannot give a reasonable explanation for this problem, the origin of matter–antimatter asymmetry remains unknown, although continuing advances in theory and improved experiment limits have ruled out some scenarios, for example, sphaleron-leptogenesis at the electroweak phase transition in the Standard Model and so on. Based on Huang’s theory of the creating of cosmic matter and my idea of the existence of energy basic state field (EBSF) in the universe, we point out the quantum turbulence generated by quantum super-fluidity in the initial period of the formation of the universe, a large number of high-energy solitons (matter) are formed after the Big Bang, it is called Huang-yang mechanism, which is different from the mechanism of antimatter creation and annihilation. In this paper, we also research that the production and annihilation of positive and negative matter promote to further evolving nuclear synthesis to form nucleons. It is absolutely not a perfect mirror symmetry between matter and antimatter when universe creations primordial matter.
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