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High-frequency induction brazing Al/Steel dissimilar metals with different composition Zn Al filler metals was performed. Before the brazing experiment, the wettability of the filler metals on steel and aluminum alloy plates was investigated, respectively. The results shown that the Zn 15Al (wt%) filler metal had the best wettability on the aluminum. The brazing experiment indicated that when the brazing gap was 0.3 mm, the maximum wetting length and best filling performance of the joint were obtained. The most serious dissolution of aluminum in the brazing seam was observed when using Zn 2Al filler metal. The three-layered structures, which were composed of IMCs layer, Zn rich layer (occurred in particular situation) and Zn Al eutectoid structure, were found near the steel interface. Experiments and thermodynamic calculations were applied for analyzing microstructure evolution and elemental diffusion behavior. The highest shear strength reached 81.52 MPa when the Zn 15Al filler metal was used in 773 K for 30 s. The fracture morphology indicating that brittle fracture occurred in all the joints. But partial breaking in filler metal not in the IMCs layer, which means that the Zn Al filler metal improved the shear strength of the joint.

Cerebral lateralization, which is often reflected in an individual's behavioral laterality (e.g., handedness and footedness), may bring animals certain benefits such as enhanced cognitive performance. Although the lateralization-cognition relationship has been widely studied in humans and other animals, current evidence supporting their relationship is ambiguous and warrants additional insights from more studies. Moreover, the lateralization-cognition relationship in non-human animals has been mostly studied in human-reared populations, and investigations of wild populations are particularly scarce. Here, we test the footedness of wild-caught male yellow-bellied tits (Pardaliparus venustulus) and investigate its association with their performance in learning to solve a toothpick-pulling problem and a drawer-opening problem. The tested birds showed an overall trend to gradually spent less time solving the problems, implying that they learned to solve the problems. Left- and right-footed individuals showed no significant differences in the latency to explore the experimental apparatuses and in the proportions that completed and did not complete the tasks. However, the left-footed individuals learned faster than the right-footed individuals in the drawer-opening experiment, indicating a potential cognitive advantage associated with left-footedness. These results contribute to the understanding of the behavioral differences between differently footed individuals and, in particular, the relationship between lateralization and cognitive ability in wild animals.

A laser beam joining an Al-on-steel overlap configuration of 5052 aluminum alloy and Q235 steel was conducted with Sn-30Zn filler wire. The influence of processing parameters on weld appearance was investigated. The microstructures and mechanical property of the joints were analyzed. The results show that Sn-Zn filler wire could well wet 5052 aluminum alloy and the steel under heating of defocusing laser. Good weld appearance was obtained by suitable processing parameters. The solid solution interface was formed at the aluminum alloy side and intermetallic compounds (IMCs) interface was formed at the steel side. With increasing laser power, intergranular penetration of the Al side aggravated, and the thickness of the IMCs layer at the steel side increased. It was found that all of the joints fractured in the seam according to the results of the tensile tests. The intergranular penetration and IMCs did not reduce the mechanical property of the joint. The maximum value of fracture load reached 312 N/mm. The fractured surface was characterized as a ductile fracture. The influence of processing parameters on the microstructures and mechanical property was discussed.

Although welding structures with Ni/Al dissimilar metals have great application potential, the interfacial metallurgy is not fully understood. The interfacial microstructures and its formation mechanisms of the Ni/Al joint were investigated by controlling the laser beam offset toward to Al side. Two modes of Ni dissolution and melting were discovered during the laser welding. When the offset was relatively big, the Ni dissolved to the weld first and then the intermetallic compounds (IMCs) formed during the welding. The IMCs consisted of Al3Ni2 in the precipitation and Al3Ni in the peritectic reaction and precipitation. The weld was divided into hypereutectic reaction zone (Hyper-ERZ) near to the interface and hypoeutectic reaction zone (Hypo-ERZ) far from the interface. When the offset was relatively small, the Ni surface layer adjacent to the weld melted first and then complex interfacial reaction occurred. The IMCs were composed of AlNi in the precipitation, Al3Ni2 and Al3Ni in peritectic reactions and precipitations. The melted layer transformed to double peritectic reaction zone(DPRZ). The weld consisted of Hyper-ERZ. With increasing the offset, the tensile strength of the joints increased first and then decreased. The highest value was up to 136.2 MPa, which is 80 % of 5052 Al tensile strength.

Low-temperature high-frequency induction brazing of 5052 aluminum alloy to stainless steel was carried out using Sn-30Zn with reactive-flux 88ZnCl2-10NH4Cl-2NaF wt.%. The influence of processing parameters on microstructures, mechanical property and fracture behavior was investigated. Intermetallic compounds were not observed at the interface of the steel. The brazing seam consisted of Sn-Zn eutectic structures, Zn-rich solid solution and oxide inclusion. The diffusion of Sn and Zn into the aluminum grain boundary led to an intergranular penetration layer. When brazing at 370°C for 30 s, the joint fractured in the brazing seam and the shear strength reached the highest at 87 MPa. The fracture surface of the joint presented ductile characteristics. The diffusion of F− in the flux made the oxide film expand and crack. Zn2+ permeated through the crack of the film and then reacted with Al, which removed the film from aluminum substrate.

The purpose of this paper is to provide the gist for the selection of filler wire during the laser welding-brazing of Al to steel. A comprehensive comparison of laser welding-brazing 5052 aluminum alloy to unbeveled galvanized steel using pure Al, AlSi5, AlMg5, AlCu6, and ZnAl2 filler wires were conducted with varied laser beam offset. The comparison was carried out in terms of weld formation, interfacial microstructures, and mechanical properties. The results show that the fluidity of liquid filler is Pure Al AlMg5 > AlCu6 > ZnAl2 > pure Al. The fracture of the joints all occurred at the brittle intermetallic layers when five different filler wires were used.

Background Research activities have often been thought to potentially influence avian nesting success by increasing nest predation rates. Although recent studies of species building open nests and cavity nests suggest that research disturbance does not generally induce nest predation, whether it is also the case in species building domed-nests remains unknown. In birds, domed-nest species exist in about half of the passerine families, and research disturbance to the domed nests may differ from that to the nests of other types for their different nest structures. Methods We investigated if research activities affected nest predation rate by analyzing the relationships of the daily nest survival rate with the research activities at the egg and nestling stages of a domed-nest species, the Silver-throated Tit (Aegithalos glaucogularis). Results Our results showed that nest daily survival rate was significantly affected by the laying date and nest age during the egg stage, and by the hatching date only during the nestling stage. By contrast, there were no significant effects of research activities, in terms of visiting nests and filming nests, on the nest survival of the Silver-throated Tit at both the egg and nestling stages. Conclusions Our results coincide with the findings in species building other types of nests that research activities do not always have negative effects on avian nesting success.

Butt joining of 5052 aluminum alloy and Q235 low carbon steel was achieved using laser beam welding with Sn-30Zn filler wire. The weld formation, microstructures, and mechanical property were investigated with varied laser power. The results show that joining of 5052 Al/Q235 steel dissimilar metals in a butt configuration by laser beam welding with Sn-30Zn filler wire is feasible. The solid solution interface formed at the aluminum side and the reaction layer formed at the steel side. With increasing laser power, the joining mode transformed from brazing to welding-brazing due to the melt of aluminum alloy. The thickness of the interfacial intermetallic compounds (IMCs) layer was also increased with laser power. However, when the laser power was 1200 W, the thickness of the interfacial IMCs layer sharply decreased due to the detachment of the IMCs layer. The fracture of the joint occurred at the steel interface and partially through the weld seam on the top surface. The fracture surface was characterized by both brittle and ductile fracture. When the joints were obtained at the laser power of 800 W and 1200 W, the tensile strength reached 79 MPa and 78 MPa, respectively. Furthermore, the formation mechanism of microstructures and its influence on mechanical property was discussed.

Behavioral lateralization, which is associated with the functional lateralization of the two brain hemispheres, commonly exists in animals and can provide an individual with benefits such as enhanced cognition and dual tasking. Lateral bias in limb use, as a type of behavioral lateralization, occur in many species, but the reasons for the coexistence of left‐ and right‐biased individuals in a population remain poorly understood. We examined the footedness of male yellow‐bellied tits (Pardaliparus venustulus) when they used feet to clamp mealworms against a perch, and tested its association with other fitness‐related behavioral traits (i.e., feeding efficiency, exploration tendency, and escape performance). We expected differently footed individuals to have respective advantages in these behaviors and thereby coexist (“respective advantage” hypothesis). We found their footedness repeatable, and there was no population‐level bias. While no associations of feeding efficiency and exploration tendency with footedness were detected, the right‐footed individuals were found to be harder to catch than the other individuals. Future studies need to investigate the reasons for the right‐footed individuals' superior escape performance. Moreover, the escape advantage for being right‐footed and the lack of population‐level bias in footedness in male yellow‐bellied tits suggest that the benefits related to left footedness also remain to be explored., Behavioral lateralization, such as handedness and footedness, commonly exists in animals, but the benefits associated with differently lateralized individuals remain poorly understood. In this article, feeding efficiency, exploration performance, and escape performance of left‐, not‐ and right‐footed yellow‐bellied tits were tested. Right‐footed individuals were found to perform better in escaping, and such a phenomenon is worthy to be investigated in more species.

To improve interfacial inhomogeneous temperature distribution and weld appearance of butt welding-brazing of steel/aluminum dissimilar metals, a hybrid heat source method combining laser penetration welding with CMT arc was developed. The Ni/Zn double coating was prepared on the surface of steel to improve the interfacial reaction and achieve fluxless process. The welding characteristics of bare steel/aluminum alloy, Ni coated steel/aluminum alloy, and Ni/Zn double coated steel/aluminum alloy were comparatively studied. Transmission electron microscope (TEM), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS) were used to analyze the interfacial microstructures of the joint. The results showed that the fluxless process were implemented by preparing Ni/Zn double coating on the surface of steel. The interfacial reaction between liquid Al and solid steel was obstructed to some extent by Ni/Zn double coating. The thickness of intermetallic compounds (IMCs) was reduced significantly. The interfacial reaction layer consisted of Fe2Al5 near the steel side and Fe4Al13 near the aluminum side. No continuous Ni-Al IMCs were found at the Fe/Al butt interface. The maximum tensile strength of Ni coated steel/aluminum joint was up to 93.4 MPa, which increased by 12% than that of the bare steel/aluminum joint. The maximum tensile strength of Ni/Zn double coated steel/aluminum joint was up to 112.6 MPa, which increased by 35% than that of the bare steel/aluminum joint. On this basis, the fluxless wetting and interfacial reaction mechanisms were revealed.

To investigate the influence of Ni coating layer on the interfacial reaction of Al/steel dissimilar metal brazing, a high-frequency brazing method of Al alloy and steel with/without a Ni coating layer were designed. The steel side interfacial microstructure of the Al/bare steel joint consisted of Fe (Al,Si)3, Al7.2Fe1.8Si. After the preparation of the Ni coating layer on the stainless steel, the interfacial microstructure consisted of Al3Ni, Al3Ni2, and residual Ni coating layer. An ultra-thin Al3Ni2 reaction layer was observed in Al/Ni-coated steel joint by transmission electron microscopy (TEM). With increasing reaction time, the Ni coating layer completely dissolved into liquid filler metal. Interfacial structure transformed into Fe(Al,Si)3/Al7.2Fe1.8Si, which was the same as that of the Al/bare steel joint. The shear strength of the joint with the Ni-coated layer increased first and then decreased with increasing brazing time, which was influenced by the dissolution level of Ni coating layer. The maximum shear strength exceeded 20.3% that of the joint without Ni coating layer. The element diffusion phenomenon in the field of the solid/liquid interface and the dissolution behavior of the Ni coating layer were analyzed by the thermodynamics method. A model of Ni dissolution kinetics was established to optimize the thickness of the Ni coating layer and the processing parameters of the brazing. The effect mechanism of Ni coating layer on the interfacial reaction of the Al/steel dissimilar metal brazing was clarified.

The interfacial reaction between solid Ni and liquid Al, such as dissolution behaviors of solid Ni and formation mechanisms of intermetallic compounds, are not thoroughly clarified yet, especially under the conditions of short holding time and high reaction temperature. In this study, a hot-dip method was designed to investigate the isothermal interfacial reaction mechanism of solid Ni and liquid Al at temperature of 700 °C, 800 °C and 900 °C for 0–40 s. The dissolution behavior of solid Ni in liquid Al was analyzed. The dissolution rate constant, KNi, and dissolution activation energy, Ea, were calculated. The microstructure analysis with scanning electron microscope (SEM) and transmission electron microscopy (TEM) revealed that the dissolved thickness of solid Ni in pure liquid Al has linear relationship with the reaction time. The microstructure of the reaction interface consisted of Ni, Ni based solid solution, Al3Ni2 layer, adhered Al3Ni layer, free Al3Ni, Al3Ni + Al eutectic structure and Al. Ni based solid solution structure firstly formed at the holding stage. Nano-scale Al3Ni2 and irregular adhered Al3Ni appeared at the interface during fast cooling stage.

Animals rely on their senses to adaptively respond to their social and non-social environment. In many animals, olfaction plays a key role in modulating social behaviour. Olfactory cues are, for example, used to discriminate kin when expressing kin-biased behaviours. Surprisingly, however, in birds the importance of olfaction in mediating social behaviour remains largely unknown, even though they are a key model in sensory ecology. Recently, there has been growing evidence suggesting that birds use olfactory cues in a range of social and non-social contexts. Furthermore, first empirical evidence suggests that competing young in the nest can recognise kin using olfactory cues. A recent experiment on wild blue tit (Cyanistes caeruleus) nestlings has shown that they beg more intensely when presented with olfactory cues from unfamiliar nestlings from a different nest compared to familiar nestlings from the same nest. Such modulation of begging behaviour in response to olfactory cues could potentially cause kin-biased begging behaviour when relatedness among competing nestlings varies due to the frequent occurrence of extra-pair paternity. However, while in natural broods nestmates may differ in relatedness due to extra-pair paternity, they are always equally familiar. Therefore, we repeated the odour discrimination experiment using cross-fostered nestlings which allowed us to test whether blue tit nestlings can also discriminate between odours of related versus unrelated conspecific nestmates which are both familiar. Focal nestlings did not beg longer to the odours of unrelated nestmates than those of related nestmates.104Hence, we found no evidence for olfactory kin discrimination. Before the start of the experiment, we preregistered our hypothesis, study design, and analysis with the Open Science Framework (OSF;https://osf.io/mghr8).