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In this study, an analytical model was established for calculating solute distribution pattern and precipitates of the Al–Mg–Si series alloys resistance spot welds. By coupling the model with a thermodynamic database, a volume element Ω was considered, then used to calculate the effective Mg and Si concentration in α-Al solid solution under different post–weld heat treatment. Resistance spot welding test of Aluminum alloys 6061 and 6082 was carried out, followed by sample characterization via transmission electron microscopy (TEM). Analysis of β-Mg2Si phase's distribution revealed that Mg and Si were segregated at the inter-granular region after welding. Notably, the β-Mg2Si phase was dissolved during post-welding solid solution treatment, thereby making Mg and Si to diffuse into the inner-granular region. This solute redistribution process was consistent with C-fS curves evolution calculated by the analytical model. The calculated effective Mg and Si concentration set up a platform for further calculation of precipitate evolution curves. Precipitate mole fraction was positively correlated with the weld's strength.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper presents the results of wettability tests by a sessile drop method coupled with residual gas analysis for the HASTELLOY® X substrates contact heated with brazing filler metal of Palnicro 36M. The contact angles formed between the substrate and the molten brazing filler metal were recorded by high-speed high-resolution CCD camera using two different heating procedures: (1) fast continuous heating to a temperature of 960 °C; (2) isothermal heating at a temperature of 995 °C for 10 min after step heating to the test temperature. In this study, the reference sample was HASTELLOY® X in a delivery state (D1). The base material with a different surface finish was also tested: after polishing (P1), after polishing and oxidation at a temperature of 600 °C for 1 h in the air (U1). The tests confirmed very good wetting properties of Palnicro 36M on HASTELLOY® X, independently on its surface finish and the heating procedure used in this study, i.e., after 10 min at 995 °C, the final contact angle values were θf = 7.6 ± 0.1°, 6.03 ± 0.07° and 6.2 ± 1.0° for D1, P1 and U1, respectively. However, oxidation of HASTELLOY® X surface affects the wetting kinetics and spreading of molten Palnicro 36M on BM substrates by: (1) increasing the initial contact angle values (θ0 = 51 ± 4°, 65 ± 13° and 83 ± 2° for D1, P1 and U1, respectively), (2) delaying the wetting process and (3) reducing the spreading area since after wettability tests at 960 °C, the largest area covered with solidified Palnicro 36M drop was noted for D1 (92 mm2) while the smallest one for U1 (52 mm2). [ABSTRACT FROM AUTHOR]

This article presents the results of structural tests of composite coatings on a NiSi2B alloy matrix containing carbides of Ti and Cr, which have been plasma surfaced from a powder mixture onto a low-alloyed steel substrate. The content and distribution of the strengthening phase in the matrix have been determined. It has been shown that the different nature of the interaction between Ti and Cr carbides and the liquid Ni alloy significantly affects the formation of composite surfacing layers as well as the distribution and content of strengthening phase particles in the matrix. [ABSTRACT FROM AUTHOR]