Copper precipitation during continuous cooling and isothermal aging of A710-type steels
Copper precipitation during continuous cooling and isothermal aging of A710-type steels
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DOI：
10.1007/bf02649816
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发表时间：
1996-06-01
影响因子：
2.8
通讯作者：
Krauss, G
中科院分区：
文献类型：
--
作者：
Thompson, SW;Krauss, G
用透射电子显微镜研究了含铜A710（也称为HSLA-80）和改性A710钢中的沉淀。淬火试样在675 ℃等温时效产生的ε-铜沉淀主要位于α-铁基体位错。沉淀物表现出多种变体的取向关系（OR）与Kurdjumov和Sachs报告的一致，精细的故障形成，并在电子衍射图案相关的条纹。对于再奥氏体化和连续冷却的试样，初次析出事件与铁素体/奥氏体界面处的铜的相间析出相关联。界面沉淀物经常显示OR以外的Kurdjumov和Sachs的报告，虽然一个独特的晶体学的变体内观察到任何一个区域的界面沉淀，故障很少观察到，和条纹没有观察到的衍射图案。在冷却过程中的高温下，形成无沉淀的铁素体，而在较低的温度下，铜沉淀物的成核发生在多边形铁素体和魏氏铁素体的晶体的铁素体/奥氏体界面。后一个特征排除了通过位移机制形成魏氏铁素体。对于粒状铁素体或针状铁素体，没有观察到相间沉淀。在连续冷却过程中，不太常见的降水事件包括AIN和CuS的形成。
Precipitation in copper-containing A710 (also referred to as HSLA-80) and modified-A710 steels was investigated by transmission electron microscopy. Isothermal aging of as-quenched specimens at 675 degrees C produced epsilon-copper precipitates located primarily at alpha-iron matrix dislocations. The precipitates exhibited multiple variants of an orientation relationship (OR) consistent with that reported by Kurdjumov and Sachs, fine fault formation, and associated streaking in electron diffraction patterns. For reaustenitized and continuously cooled specimens, the primary precipitation event was associated with interphase precipitation of copper at ferrite/austenite interfaces. Interphase precipitates frequently displayed ORs other than that reported by Kurdjumov and Sachs, although a unique crystallographic variant was observed within any one region of interphase precipitation, faults were observed infrequently, and streaking was not observed in diffraction patterns. At high temperatures during cooling, precipitate-free ferrite formed, whereas at lower temperatures, nucleation of copper precipitates occurred at ferrite/austenite interfaces for crystals of polygonal ferrite and Widmanstatten ferrite. This latter feature precludes the formation of Widmanstatten ferrite via a displacive mechanism. Interphase precipitation was not observed for granular ferrite or acicular ferrite. Less-common precipitation events during continuous cooling included the formation of AIN and CuS.