基于渗流技术制备的新型CuAlNi/Al 复合材料阻尼和力学行为

Damping and mechanical properties of novel CuAlNi/Al composites prepared by infiltration technique

  • 摘要: 选用CuAlNi形状记忆合金作为阻尼增强相,设计并制备了新型枣糕状CuAlNi/Al复合材料。制备过程主要由两个步骤组成,首先基于造孔剂颗粒的空间占位和溶除,通过粉末冶金工艺制备了CuAlNi泡沫,随后在此基础上,采用真空负压渗流技术制备了CuAlNi/Al复合材料。详细考察了复合材料的微观结构、阻尼和压缩力学性能。内耗测试表明,CuAlNi/Al复合材料可以实现超高的阻尼能力,远高于相应的Al基体,在室温附近的阻尼值甚至是纯Al的6倍。复合材料优异的阻尼能力不仅来源于CuAlNi合金增强相的高本征阻尼能力,还与CuAlNi和纯Al之间引入的弱结合界面阻尼及复合材料中与残余微孔相关的附加阻尼有关。此外,当CuAlNi/Al复合材料中Al体积分数高于59.5vol%时,具有和纯Al相似的压缩应力-应变曲线和形变机制,但呈现更高的压缩力学强度和能量吸收能力。

     

    Abstract: CuAlNi shape memory alloy is chosen as damping reinforced phase, then novel jujube-cake shaped CuAlNi/Al composites were designed and prepared. The whole preparation process can be summarized as two steps, i.e. initial production of parent CuAlNi foam by powder metallurgy process basing on space occupation and dissolution of pore-forming agent and subsequent fabrication of CuAlNi/Al composites by negative pressure infiltration. The microstructure, damping and compressive mechanical properties of the composites were investigated in details. Internal friction measurements indicate that the CuAlNi/Al composites can obtain ultrahigh damping capacity, and the value of damping near the room temperature is even 6 times relative to pure Al. The excellent damping capacity of the composite is rationalized not only to relate to high intrinsic damping of CuAlNi reinforcement, but also to associate with the weak-bonding interface damping introduced between CuAlNi and pure Al and the additional damping arising from the residual micro-pores in the composites. Moreover, the composites exhibit similar compressive stress-strain curves and deformation mechanism as pure Al when the Al volume percent in the composite is more than 59.5vol%, but higher compressive mechanical strength and energy absorption capacity.

     

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