扭摆内耗仪的发明和内耗研究的开拓与发展

DEVELOPMENT OF THE TORSlON PENDULUM AND THEEARLY RESEARCH ON GRAIN BOUNDARY RELAXATIONAND THE COLD-WORK INTERNAL FRICTION PEAK

本文对笔者关于滞弹性内耗研究的早期工作（１９４５一１９４９年于芝加哥）作了历史回顾。概述用滞弹性测量方法研究了金属中晶粒间界和滑移带的力学性质，并为此目的而创制了扭摆内耗仪和转动线圈的扭转装置，从而可以用同一试样测定内耗、动态模量亏损，在恒应力下的蠕变和在恒应变下的应力弛豫。首次观测到晶粒间界内耗峰（作为温度的函数），测出了晶界弛豫的激活能，提出了大角晶界的＂无序原子群＂模型；在部分再结晶的冷加工金属试样中观测到与滑移带弛豫有关的内耗峰，在冷加工并经过部分退火的含铜的铝中发现了反常内耗峰（作为温度和应变振幅的函数）。最后指出，近年来在晶界弛豫和位错弛豫的研究中发现了大量非线性滞弹性现象，基本上奠定了非线性滞弹性理论的实验基础，标志着非线性滞弹性这一新学科领域的开端。

This paper gives a historical rcview of the early research on anelas-ticity during the author,s stay at Chicago (1945-1949). The rcsearch topicssuggested initially by Professor C. Zener, the founder of the concept of anelas-ticity, include the studies of the mechanical properties of grain boundaries andthe slip bands in metals by anelastic measurements. The torsion pendulum andthe moving coil twisting arrangement wcrc dcvelopcd for this purpose so that in-ternal friction, dynamics modulus defcct, creep under constant stress and stressrelaxation at a constant strain can be measured with the same specimen.The grain boundary peak(versus temperature)was obscrved for the first time.A 'disordered atom groupsn model for high-angle grain boundaries was suggestedmainly in virtue of the succcss in measuring the activation energy associatedwith grain boundary relaxation.Similar internal friction peaks associated with slip band relaxation wereobserved in partially recrystallized cold-workcd metals. And anomalous internalfriction peaks were discovercd in cold-worked and partially annealed Al-Cu solidsolutions .In conclusion, a short description of the rcscarch performed in China, afterthe Chicago period, on grain boundary relaxation and anomalous internal frictionwas given, including the emergence of non-linear anelasticity.