【摘要】 用选区激光熔融技术（SLM）制备Al-30Si合金，研究了去应力退火后样品的显微组织、力学性能和热物理性能。结果表明：SLM成形的Al-30Si合金样品经300℃/6 h退火后其室温抗拉强度为254±3 MPa，比铸态加工的Al-30Si合金的抗拉强度提高53.5%，硬度为176.89±8.5HV、比刚度为35.18 m²/s²。SLM成形样品温度为-100℃～200℃时的热膨胀系数为13.8×10^-6/℃～16.3×10^-6/℃，平均热导率为70.52 W·m^-1·K^-1。快速冷却的特性能够细化SLM成形样品的初晶Si颗粒，使成形Al-30Si合金具有较好的综合性能，其高比刚度和较低的热膨胀系数有望使服役于特殊环境的光机结构件保持高度的尺寸稳定性。更多还原

【Abstract】 The bulk material of the hyper-eutectic Al-30Si alloy was prepared via selective laser melting（SLM） technique, aiming to solve the problem of high brittleness, easy cracking, and difficulty in precise forming caused by the coarsening of primary Si in the alloy due to the coarsening of primary Si particles in the alloy during ordinary making process. Then the microstructure, mechanical properties, and thermal properties of the SLM alloy after stress-relief annealing were studied. The results showed that the room temperature tensile strength of the SLM Al-30Si alloy after annealing was 254 ± 3 MPa, which was 53.5% higher than that of the cast alloy. The hardness was 176.89 ± 8.5 HV and the specific stiffness was 35.18 m²/s². In terms of thermal properties, the thermal expansion coefficient of the SLM Al-30Si alloy is 13.8 to 16.3 × 10^-6/oC in the temperature range of-100～200oC, and the average thermal conductivity is 70.52 W·m^-1·K^-1. The study found that the rapid cooling characteristic of SLM could refine the primary Si particles, making the formed Al-30Si alloy have good comprehensive properties. The high specific stiffness and low thermal expansion coefficient are expected to maintain high dimensional stability for optical components.更多还原