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利用系列冲击法、Auger电子能谱(AES)、扫描电镜(SEM)研究了含450ppm P的Ni-Cr钢的480℃等温脆化过程(0—1000h)以及磷和某些合金元素在原奥氏体晶界的偏聚行为。试验钢的韧脆转变温度(FATT)在480℃等温的最初20h内急剧增高,随后渐趋平稳。与此同时,原奥氏体晶界P含量也呈现出同样的行为,钢的FATT与晶界P量成正比。P的偏聚范围相当窄,等温1000h后集中在距晶界大约10A以内。除P在晶界偏聚外,还发现有合金元素Ni、Cr和Mn的晶界偏聚现象,而且Ni的偏聚量与晶界P成正比。证实了杂质原子P和合金元素Ni、Cr、Mn共同向原奥氏体晶界偏聚是引起Ni-Cr钢回火脆性的根本原因。
The isothermal embrittlement at 480 ℃ (0-1000h) of Ni-Cr steels with 450ppm P and the effect of phosphorus and some alloying elements on the original austenite Partitioning behavior of bulk grain boundaries. The ductile-brittle transition temperature (FATT) of the test steels steeply increased during the first 20 hours of isothermal at 480 ° C and then gradually stabilized. At the same time, the original austenite grain boundary P content also showed the same behavior, the steel’s FATT and grain boundary P is proportional to the amount. P partial polymerization range is quite narrow, 1000h after the focus on the grain boundary within about 10A. In addition to P segregation at the grain boundaries, but also found alloying elements Ni, Cr and Mn grain boundary segregation phenomenon, and Ni segregation is proportional to the grain boundary P. Confirmed that the impurity atoms P and the alloying elements Ni, Cr and Mn coalesced to the original austenite grain boundaries are the basic causes of temper embrittlement of Ni-Cr steel.