铝基非晶态合金的研究进展

铝基非晶态合金及其非晶复合材料具有高强、高韧、轻质、廉价、耐蚀等特点,具有广阔的应用前景。就该领域玻璃形成能力、热稳定性及纳米晶化等热点问题进行了较详尽的综述。Trg准则不适用于判断铝基合金的玻璃形成能力,无玻璃转变的合金亦可具有强的玻璃形成能力。纳米晶化产物的小尺寸是由析出物周围溶质富集、阻碍长大造成的;高密度成因仍存在分歧。

Micro-scale mechanics of the surface-nanocrystalline Al-alloy material

Based on the microscopic observations and measurements, the mechanical behavior of the surface-nanocrystallized Al-alloy material at microscale is investigated experimentally and theoretically. In the experimental research, the compressive stress-strain curves and the hardness depth curves are measured. In the theoretical simulation, based on the material microstructure characteristics and the experimental features of the compression and indentation, the microstructure cell models are developed and the strain gradient plasticity theory is adopted. The material compressive stress-strain curves and the hardness depth curves are predicted and simulated. Through comparison of the experimental results with the simulation results, the material and model parameters are determined.

超声喷丸对7075铝合金棒材组织结构与性能的影响

研究了超声喷丸对7075铝合金棒材微观组织结构、显微硬度、电化学腐蚀以及晶间腐蚀行为的影响。金相、XRD以及TEM等结果表明,采用超声喷丸制备了表层晶粒尺寸约为78.2 nm的梯度纳米结构7075铝合金,且合金表层时效析出强化相(η和η′相)回溶基体。显微硬度结果表明,超声喷丸处理后合金表层硬度提升了约20%。在0.1 mol/L Na_(2)SO_(4)+20 mmol/L NaCl溶液中的极化曲线结果表明,合金在超声喷丸处理后点蚀电位正移,说明合金耐点蚀萌生能力增强。在3.5%NaCl溶液中的极化曲线与电化学阻抗谱结果表明,7075铝合金棒材在超声喷丸处理后腐蚀速率加快,且腐蚀速率在深度方向上呈递减趋势。晶间腐蚀浸泡实验表明7075铝合金在超声喷丸处理后耐晶间腐蚀能力降低。最后,讨论了超声喷丸7075铝合金棒材的表层强化机制与腐蚀机理。