层间硬度比对Cu-Be/Cu层状异构复合材料强韧性的影响

Effect of layer hardness ratio on strength and toughness of Cu-Be/Cu layered composite materials with heterostructure

  • 摘要: 通过真空热压复合、冷轧及热处理的方式制备了具有不同层间硬度比(RCu-Be/Cu分别为3.0、 5.0、 7.0)的Cu-Be/Cu层状异构复合材料。研究了层间硬度比RCu-Be/Cu对复合材料强度-塑性匹配及应变硬化率的影响,探索了不同RCu-Be/Cu下异质变形诱导强化对复合材料应变硬化行为的影响。研究结果表明,随着RCu-Be/Cu升高,层状异构复合材料的抗拉强度升高、均匀伸长率降低,但复合材料抗拉强度均高于依据混合定律计算值,且均匀伸长率均高于相应Cu-Be组元,其中RCu-Be/Cu为5.0的复合材料具有最优强度-塑性匹配。异质变形诱导强化作用可使层状异构复合材料中产生额外应变硬化,但RCu-Be/Cu为3.0的复合材料中异质变形诱导强化产生的应变硬化作用较弱,而RCu-Be/Cu为7.0的复合材料中异质变形诱导硬化作用在塑性变形初期就达到饱和状态并迅速降低,RCu-Be/Cu为5.0的复合材料中异质变形诱导硬化在材料应变硬化过程中占据主导作用,且可在较大应变范围内为材料提供额外应变硬化能力。

     

    Abstract: The Cu-Be/Cu layered heterogeneous composite materials with different layer hardness ratios (RCu-Be/Cu=3.0, 5.0, 7.0) were prepared by vacuum hot pressing bonding, cold rolling and subsequent heat treatments. The effects of RCu-Be/Cu with different interlayer hardness ratio on the balance of strength and ductility and the strain hardening rate of the composites were investigated. Furthermore, the effect of heterogeneous deformation induced (HDI) hardening on the strain hardening behavior of composites with different RCu-Be/Cu was also studied. The results show that the ultimate tensile strength increases and the uniform elongation decreases with the increase of the interlayer hardness ratio. However, the ultimate tensile strength of the composites is higher than the value calculated by the rule of mixture (ROM). Moreover, the uniform elongation is also higher than that of the corresponding Cu-Be component, among which the composites with RCu-Be/Cu of 5.0 possess the best balance of strength and ductility. The extra strain hardening effect in the layered composite materials with heterostructure can be caused by HDI hardening. The effect of HDI hardening on strain hardening is relatively weak in the composites with RCu-Be/Cu of 3.0, while the HDI hardening in the composites with RCu-Be/Cu of 7.0 reaches saturation at the initial stage of plastic deformation and then decreases rapidly. The HDI hardening in the composites with RCu-Be/Cu of 5.0 plays a dominant role during the strain hardening process and provides the extra strain hardening effect for the composites within a large strain range.

     

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