Prestrain, Cavitation, and Creep Ductility
Prestrain, Cavitation, and Creep Ductility
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预应变、气蚀和蠕变延展性
DOI：
10.1179/msc.1974.8.1.261
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发表时间：
1974
期刊：
影响因子：
--
通讯作者：
M. Rodgers
中科院分区：
文献类型：
--
作者：
B. Dyson;M. Rodgers
Nimonic 80 A的试样在室温下以不同的量在拉伸中预应变，直至15%的伸长率。每个预应变试样在750° C下以154 N/mm 2或460 N/mm 2两种应力之一进行蠕变，这两种应力分别给出1800和5 h的未预应变蠕变寿命。有些试验在160 h后中断，但大多数试样断裂。在这两种应力下，材料的蠕变强度、寿命和断裂韧性随着预应变的增加而逐渐丧失，而定量光学金相分析显示，晶界空腔的数量随之急剧增加。空洞密度和尺寸测量已经确定，蠕变延性降低是因为空洞密度增加，而不是因为空洞生长速率的任何增加。这表明，蠕变强度的损失可能是由于冷加工的移动的位错含量的增加。
Specimens of Nimonic 80A have been prestrained in tension at room temperature by various amounts up to 15% elongation. Each prestrained specimen was crept at 750° C at one of two stresses, 154 N/mm2 or 460 N/mm2, which gave unprestrained creep lives of 1800 and 5 h, respectively. Some of the tests were interrupted after 160 h but most specimens were fractured. At both stresses, the material suffered progressive loss of creep strength, life, and fracture ductility as prestrain increased, while quantitative optical metallography revealed a concomitant dramatic increase in the number of grain-boundary cavities. Cavity density and size measurements have established that creep ductility is reduced because of increased cavity density and not because of any increase in cavity growth rate. It is suggested that the loss in creep strength is probably due to an increase in the mobile dislocation content with cold work.