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本文对稀土元素含量(铈和镧含量的总和为:0,0.011,0.026,0.037,0.075,0.124％)不同的工业纯铁样品,在充分去碳、氮后进行了内耗测量。结果指出:铁的晶界激活能随稀土元素含量的变化出现极大值。这个极大值出现在稀土元素含量约0.03％左右,其值为11.3×10~4卡/克分子,比不含稀土元素的铁样品(6.4×10~4卡/克分子)约高一倍。对渗碳样品进行内耗测量得出:晶界内耗峰较充分去碳、氮样品的晶界内耗峰有近30℃的较大移动,各样品的晶界激活能趋近相等为7.6×10~4卡/克分子(实验误差在±2000卡/克分子以内)。 对碳在铁中的斯诺克峰的测量得出:随铁中稀土元素含量的增加,峰的高度被降低,而峰的位置和铁的比较,并没有变化。 对各样品的冷加工内耗测量得出:未去碳和氮的原始样品(断面缩减率为88％)的冷加工内耗峰出现在230℃附近,峰值随稀土元素含量的增加而显著降低。对样品充分去碳、氮以后再重新渗氮,并进行冷加工(断面缩减率为88％),则冷加工内耗峰出现在190℃,这个峰也随着稀土元素含量的增加而显著降低。 本文对于铁的这三个内耗峰(晶粒间界峰,斯诺克峰,冷加工峰)随着稀土元素含量而发生变化的可能原因,进行了初步的讨论。
In this paper, rare earth elements (cerium and lanthanum content of the total: 0,0.011,0.026,0.037,0.075,0.124%) different industrial pure iron samples, after full carbon, nitrogen internal friction measurement. The results show that: the grain boundary activation of iron with the maximum content of rare earth elements. This maximum appears about 0.03% for rare earth elements, which is about 11.3 × 10 ~ 4 cal / mol, which is about twice as high as that for rare earth-free iron samples (6.4 × 10 ~ 4 cal / mol) . The internal friction measurements of carburized samples show that: the peak of the grain boundary is more fully de-carbonized; the peak of the peak of nitrogen in the grain boundary of the sample moves nearly 30 ° C; the activation energy of the grain boundaries in each sample approaches to equal to 7.6 × 10 ~ 4 calories per gram (experimental error is within ± 2,000 calories per mole). The measurement of the Snock peak of carbon in iron shows that as the content of rare earth elements in the iron increases, the height of the peak is reduced and the peak position and the iron are not changed. The internal friction measurement of each sample shows that the internal friction peak of cold working of the original sample without carbon and nitrogen (the reduction of area is 88%) appears near 230 ℃, and the peak value decreases remarkably with the increase of rare earth element content. After the sample was fully de-carbonized and nitrogen was re-nitrided and cold worked (reduction of area was 88%), the internal friction peak at cold working occurred at 190 ° C. This peak also decreased significantly with the increase of rare earth element content. In this paper, the possible reasons why the three internal friction peaks (intergranular peak, snooker peak and cold working peak) of iron change with the content of rare earth elements are discussed.