Balancing increased recoverable strain with high phase transformation temperature is crucial for Cu-Al-Mn SMAs to cost-effectively overcome the service temperature limitation (<100°C) of NiTi-based SMAs. This study fabricated four types of Cu-12.5Al-3Mn SMAs modified with nano-Al₂O₃ p (0, 0.5, 1.0, and 1.5 wt%) using wire arc additive manufacturing (WAAM) with cored wires. It investigated the effects of nano-Al₂O₃ p on shape memory properties, exploring mechanisms via microstructural, phase, and hardness analysis. Results show that adding an appropriate amount of nano-Al₂O₃ p significantly enhances memory performance while maintaining high martensite transformation temperatures. The 0.5 wt% nano-Al₂O₃ p modified alloy exhibited optimal properties: a shape recovery rate of 87.77 % (13.8 % higher than the base alloy) and a recoverable strain of 7.02 % (>40 % higher than the commonly reported 5 %) under 8 % bending pre-strain. Its Ms temperature remained above 100°C (As, Af, Mf were largely unchanged), and full recovery time was halved compared to the unmodified alloy. The enhancement is attributed to nano-Al₂O₃ p strengthening the parent phase and improving thermoelastic martensite order via pinning. Their high stability under WAAM's high-energy heat source minimizes impact on alloy composition, while dispersed particles create lattice distortion and stress fields, reducing the energy barrier for martensitic transformation.
To address the thermal management challenge in phosphor-in-glass (PiG) materials for laser lighting due to low glass matrix thermal conductivity, this study developed YAG:Ce 3+ -Al 2 O 3 PiG composites reinforced with Al 2 O 3 particles, achieving a thermal conductivity of 78.6 W/(m·K). A TiO 2 reflective layer optimized for reflection and light conversion was introduced between the AlN substrate and PiG layer. Systematic optimization of Al 2 O 3 content and preparation conditions yielded YAG:Ce 3+ -Al 2 O 3 PiG composites with exceptional performance: maximum luminous flux (LF) of 2515 lm under blue laser excitation, saturation threshold (ST) of 27.57 W/mm 2 , and luminous efficiency (LE) of 174.7 lm/W. LF and ST increased by 184.5 % and 167.4 %, respectively, compared to non-Al 2 O 3 counterparts. The surface temperature of 9 wt% Al 2 O 3 PiG reached 363.85 K, 34.4 % lower than the working temperature of the sample without Al 2 O 3 addition. Stable light emission and high photothermal stability confirm its potential as a high-brightness laser lighting material.
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