High Temperature Mechanical Spectroscopy in Ordered Ni3(Al, Ta)
High Temperature Mechanical Spectroscopy in Ordered Ni3(Al, Ta)
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有序 Ni3(Al, Ta) 的高温机械光谱
DOI：
10.1051/jp4:1996850
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
R. Schaller
中科院分区：
文献类型：
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作者：
A. Mourisco;N. Baluc;J. Bonneville;R. Schaller
对具有L12有序结构的Ni3（Al，1%Ta）合金的多晶和单晶样品（三种不同取向）进行了机械损耗测量。测量进行了扭转摆，在铸态样品和样品预变形无论是在300 K或在1300 K，并揭示了两个主要现象的发生：（a）存在一个明确的内部摩擦峰的温度约为950 K的频率为1 Hz。该弛豫峰具有约3eV的活化能，并且其幅度强烈依赖于样品取向和预变形条件。(b)高温（1100K以上）时的内耗背景主要取决于应变幅和预变形条件。这两种现象出现密切相关的点缺陷的存在下，superdislocations的复杂的解离模式和位错机制的变化发生在峰值温度的流动应力（约800 K）的关系，在活动的滑移系统的变化。
Mechanical loss measurements were performed on polycrystalline and single crystalline samples (of three different orientations) of a Ni 3 (Al,1%Ta) alloy with the L12 ordered structure. Measurements were conducted in torsion pendula, on as-cast samples and samples predeformed either at 300 K or at 1300 K, and revealed the occurrence of two main phenomena: (a) The presence of a well-defined internal friction peak at a temperature of about 950 K for a frequency of 1 Hz. This relaxation peak has an activation energy of about 3 eV and its amplitude is strongly dependent on sample orientation and predeformation conditions. (b) An internal friction background, which amplitude at high temperatures (above 1100 K) mainly depends on strain amplitude and predeformation conditions. Both phenomena appear closely related to the presence of point defects, to the complex dissociation mode of superdislocations and to the change in dislocation mechanisms occurring at the peak temperature in flow stress (about 800 K) in relationship with a change in active slip systems.