Solid solution hardening evaluated from amplitude-dependent internal friction in polycrystalline copper alloys
Solid solution hardening evaluated from amplitude-dependent internal friction in polycrystalline copper alloys
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DOI：
10.1016/s1359-6462(99)00139-6
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发表时间：
1999-06-18
影响因子：
6
通讯作者：
Asano, S
中科院分区：
文献类型：
--
作者：
Ide, N;Yamashita, M;Asano, S
迄今为止，固溶硬化是通过拉伸试验评估的流动应力来研究的。流变应力取决于位错的迁移率和增殖率两个因素，因此很难区分这两个因素对固溶硬化的影响。另一方面，仅由位错的迁移率控制的机械性能可以通过测量振幅相关的内摩擦来研究，因为内摩擦是在不发生位错倍增的试样的弹性共振期间测量的。这样的机械性能的调查还没有经常尝试的基础上的内部摩擦测量。Bauer等人(1-3)测量了单晶Cu合金中的振幅相关的内部摩擦，但他们没有从固溶体硬化的观点讨论对应于宏观应力-应变关系的机械性能。浅野（4）提出了一种方法来评估微塑性应变的振幅依赖性的内部摩擦的数据，其中试样受到宏观弹性变形。根据该方法，Polotskiy等人首次从单晶Cu-Mg合金的内耗数据计算了微塑性应变。（五）、后来，该方法已被应用到几个单晶和多晶材料（6-9）。近年来，Lebedev和Pilecki（10）研究了工程用多晶硅青铜的力学性能，在本研究中，我们在流动应力仅由位错的迁移率控制的条件下，根据多晶Cu合金的振幅相关的内耗数据评估了塑性应变作为应力的函数。在我们的测量中，多晶合金被用作试样，因为内耗的振幅依赖性太结构敏感，在高纯单晶中显示可重复的结果。此外，塑性应变的测量方法有望作为一种新的无损强度测试方法应用于工程材料。溶质元素被限制在IVb组内，并且浓度被固定在0.3%，以检查流动应力对溶质和溶剂原子之间的尺寸失配的依赖性。
Solid solution hardening has so far been investigated through the flow stress evaluated by tensile tests. The flow stress depends on two factors, ie mobility and multiplication rate of dislocations, and thus it is difficult to distinguish the effects of the two factors on solid solution hardening. On the other hand, mechanical properties controlled only by the mobility of dislocations can be investigated through measurements of amplitude-dependent internal friction, because internal friction is measured during elastic resonant vibration of specimens where the multiplication of dislocations does not take place. Such an investigation of mechanical properties has not often been attempted on the basis of internal friction measurements. Bauer et al.(1–3) measured the amplitude-dependent internal friction in monocrystalline Cu alloys, but they did not discuss the mechanical properties corresponding to macroscopic stress-strain relations from the standpoint of solid solution hardening. Asano (4) proposed a method to evaluate the microplastic strain from data of the amplitude-dependent internal friction where specimens are subject to macroscopically elastic deformation. According to this method, the microplastic strain was firstly evaluated from the internal friction data in monocrystalline Cu-Mg alloys by Polotskiy et al.(5). Later, the method has been applied to several monocrystalline and polycrystalline materials (6–9). In a recent year, Lebedev and Pilecki (10) studied the mechanical properties of polycrystalline silicon bronze for engineering use.In the present study, we evaluated plastic strain as a function of stress from data of the amplitudedependent internal friction in polycrystalline Cu alloys under the condition that the flow stress is controlled only by the mobility of dislocations. The polycrystalline alloys were employed as specimens in our measurements, because the amplitude dependence of internal friction is too structure-sensitive to show reproducible results in highly pure monocrystals. In addition, the application of the present evaluation of plastic strain to engineering materials is expected as a new non-destructive strength test. The solute elements were restricted within IVb group and the concentration was fixed at 0.3% in order to examine the dependence of flow stress on the size misfit between solute and solvent atoms.