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Glass lubricant with a suitable viscosity is critical for the efficient production of high‐quality titanium alloy in hot extrusion process. In this study, a new glass lubricant, (30.93‐0.309x)B2O3‐(48.45‐0.485x)SiO2‐(7.22‐0.072x)Al2O3‐(13.4‐0.134x)Na2O‐xBaO (BSANB), was proposed for titanium alloy hot extrusion. The effect of BaO content varying from 0 wt.% to 15 wt.% on its viscosity was investigated, and the mechanism of viscosity change was clarified through melt structure analysis by using molecular dynamics (MD) simulation, X‐ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The glass viscosity was measured in the temperature range of 950°C to 1100°C, and the atomic self‐diffusion coefficient of the glass melt was calculated. The results demonstrated that the BaO content has a significant influence on the viscosity of the BSANB glass at the hot extrusion temperature range. The viscosity value at 950°C was decreased by 52.87%, from 103.5 Pa·s to 48.8 Pa·s, when BaO content was increased from 0 wt.% to 15 wt.%. MD simulation results of the BSANB glass show that the self‐diffusion coefficient of Si atoms was lower than that of Al and B atoms, indicating that Si‐O bonds were more stable in the melt. The diffusion coefficient of Si atom was directly related to the rheological behavior of the melt, which can be reflected by the melt viscosity. The results of MD simulation, XPS and Raman spectral fitting at 950°C showed an increase in the amounts of Q1, Q0 and [BO4], while the amounts of Q2, Q3, Q4 and [AlO4] were decreased when BaO content was increased from 0 wt.% to 15 wt.%. This demonstrated that the melt network was depolymerized with an increased BaO content, which determined the melt viscosity change. In addition, the mechanism responsible for glass viscosity reduction due to temperature increase was also discussed. [ABSTRACT FROM AUTHOR]

Glass lubricant with a suitable viscosity is essential for producing high‐quality titanium products by the hot extrusion process. In this study, a novel lubricant of B2O3–SiO2–Al2O3–Na2O–TiO2 (BSANT) glass was proposed, where the effects of B2O3/SiO2 molar ratio (B/Si) and B2O3 content on viscosity and structure were investigated. The results showed that the BSANT glass viscosity was gradually decreased, and the viscous activation energy was decreased by 20.24% with an increased B/Si ratio from 0.415 to 0.719. This was attributed to the decreased amounts of Q3, [BO4], [AlO4], and bridging oxygen (BO) in the network structure, which in turn resulted in a decreased network degree of polymerization. When B2O3 content was increased from 18.70 to 33.12 mol.%, the melt viscosity value at 950 ℃ was decreased by 64.51%, and the viscous activation energy was reduced by 15.82%. Boron anomalies were also observed in glass melts with the B2O3 content from 28.28 to 33.12 mol.%. The mechanisms responsible for this phenomenon were thoroughly discussed in the study. Additionally, a comparison and discussion of the applications of glass lubricants in metal hot working were presented. A glass lubricant with a specific composition was recommended for use in hot extrusion process within the temperature range of 950–1100°C due to its relatively stable viscosity properties. A novel lubricant of B2O3–SiO2–Al2O3–Na2O–TiO2 (BSANT) glass was proposed, where the effects of B2O3/SiO2 molar ratio (B/Si) and B2O3 content on viscosity and structure were investigated. A glass lubricant with a specific composition was recommended for use in hot extrusion process within the temperature range of 950–1100°C due to its relatively stable viscosity properties. [ABSTRACT FROM AUTHOR]

A-type granites typically exhibit enrichment and mineralization of critical metals such as molybdenum and tin, essential for emerging technologies. However, the key factors influencing their mineralization potential remain elusive. The scarcity of studies on barren systems impedes the understanding of this question. Here, a detailed melt and fluid inclusion study was conducted on the barren Wushan pluton to reconstruct its magmatic evolution and magmatic–hydrothermal transition and explore the factors controlling the metallogenic potential of Mo and Sn in A-type granites. The Wushan pluton displays apparent lithological zoning consisting of two major phases, i.e. medium-grained seriate to porphyritic alkali feldspar granite and fine-grained porphyritic granite. Miarolitic cavities are widely developed in each lithofacies. The silicate melt inclusions from two granitic phases are rhyolitic, with moderate F contents (0.06–0.53 wt %) and depleted H2O contents (2.0–3.5 wt %). Melt inclusions show a wide range of incompatible element contents, such as Cs (9–1977 μg/g) and Rb (268–2601 μg/g), suggesting that Wushan has undergone a high degree of magma evolution. Mo behaves incompatibly in the magmatic evolution, and its content is enriched with the increasing degree of fractional crystallization, but remains constant after the Cs content exceeds 50 μg/g. Rayleigh fractionation model suggests that a large amount of Mo is extracted from fluid exsolution, which restrains Mo from further enrichment. In contrast, Sn behaves as a mildly incompatible element during the entire magmatic evolution history. The contents of Sn increase slowly compared to the trend of Mo, and the maximum contents reach ~30 μg/g in the highly evolved melts. The separation and crystallization of Sn-bearing minerals such as biotite, magnetite, and titanite inhibit the enrichment of Sn. Intermediate-density (ID-type) fluid inclusions hosted in the miarolitic quartz, representing the initial fluid exsolving from magma, display high Mo but low Sn concentrations. Constrained from two assemblages of coexisting ID-type fluid and melt inclusions, the fluid/melt partition coefficients of metals are obtained, with D Mo, fluid/melt at 16–19, while D Sn, fluid/melt is only about 1. The comparison between Mo-mineralized and barren intrusions worldwide shows that the metal contents in melts and fluids are not fundamentally different. The mineralized intrusions are characterized by the lower melt viscosity and the development of apophyses, both of which facilitate the extraction of metals and fluids from large magma chambers, followed by their concentration into a small rock volume. Consequently, it appears that physical and structural conditions rather than chemical compositions play a crucial role in the Mo mineralization process. Enrichment of Sn in melts is necessary but not decisive for Sn mineralization, whereas Sn enrichment in the initial exsolving fluid determines the Sn mineralization potential of a given granitic system. Compared to Sn enrichment in source melting and fractional crystallization which commonly enhance final Sn fertility in the highly evolved melts, the efficiency of Sn partitioning between melt and fluid plays a fundamental role in converting melt fertility into Sn-enriched fluids and thereby high mineralization potential of the magmatic–hydrothermal system. Our findings suggest a prospect for Mo exploration in the coastal A-type granite belt in South China, while the potential for Sn mineralization is expected to be limited. [ABSTRACT FROM AUTHOR]