快速凝固-粉末冶金工艺制备高强阻尼铝合金的阻尼性能(英文)

采用快速凝固-粉末冶金(RS-PM)工艺制备两种不同类型的高强阻尼铝合金(LZ7),一种是直接挤压成型材,另一种是先挤压至棒材再轧制成板材。利用阻尼机械热分析仪(DMTA)在25~300°C下对其进行阻尼性能测试,利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)观察材料的微观组织。结果表明,随着温度的升高材料的阻尼性能提高,在300°C时板材的内耗值高达11.5×10-2,型材的内耗值达到6.0×10-2和7.5×10-2。轧制板材的内部析出相的颗粒形貌较挤压型材的析出相更规则,分布更均匀;板材中颗粒相与基体结合较疏松。基体与颗粒相结合情况的不同可以解释板材在高温阶段(120°C)阻尼性能优于型材阻尼性能的原因。

Damping capacity of high strength-damping aluminum alloys prepared by rapid solidification and powder metallurgy process

Two kinds of high strength-damping aluminum alloys (LZ7) were fabricated by rapid solidification and powder metallurgy (RS-PM) process. One material was extruded to profile aluminum directly and the other was extruded to bar and then rolled to sheet. The damping capacity over a temperature range of 25-300 °C was studied with damping mechanical thermal analyzer (DMTA) and the microstructures were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results show that the damping capacity increases with the test temperature elevating. Internal friction value of rolled sheet aluminum is up to 11.5×10-2 and that of profile aluminum is as high as 6.0×10-2 and 7.5×10-2 at 300 °C, respectively. Microstructure analysis shows the shape of precipitation phase of rolled alloy is more regular and the distribution is more homogeneous than that of profile alloy. Meanwhile, the interface between particulate and matrix of rolled sheet alloy is looser than that of profile alloy. Maybe the differences at interface can explain why damping capacity of rolled sheet alloy is higher than that of profile alloys at high temperature (above 120 °C).