采用Gleeble-1500D热模拟试验机,在变形温度为900~1250℃、应变速率为0.001~1 s^-1的条件下对铸态ER8车轮钢进行热压缩试验,得到真应力-真应变曲线。结果发现:其真应力-真应变曲线符合动态再结晶型软化机制,变形初始阶段,材料发生硬化,...采用Gleeble-1500D热模拟试验机,在变形温度为900~1250℃、应变速率为0.001~1 s^-1的条件下对铸态ER8车轮钢进行热压缩试验,得到真应力-真应变曲线。结果发现:其真应力-真应变曲线符合动态再结晶型软化机制,变形初始阶段,材料发生硬化,真应力快速增加,随着变形的继续,材料发生动态回复,加工硬化速率减缓;在材料变形过程中,材料畸变的应变储存能增加,动态再结晶激活,真应力迅速降低,后硬化及软化达到动态平衡。并分析了变形温度和应变速率对该材料高温下真应力的影响,发现真应力的大小随着变形温度的升高及应变速率的降低而减小。通过对试验数据的归纳整理得出,铸态ER8车轮钢的热变形激活能为258.4 k J·mol^-1。建立了Arrhenius双曲正弦本构方程,用作图法求解加工硬化速率,找出峰值应变及临界应变,基于此建立动态再结晶体积分数模型。其能精准地预测此材料的高温软化行为,为有限元数值模拟提供了理论基础。展开更多
Zagros orogenic belt has developed on northern-eastern edge of Arabian plate from Northern-Western-Southern-Eastern Turkey to Strait of Hormuz with a length of over 2000 km. Thick sedimentary series of the Zagros (6 -...Zagros orogenic belt has developed on northern-eastern edge of Arabian plate from Northern-Western-Southern-Eastern Turkey to Strait of Hormuz with a length of over 2000 km. Thick sedimentary series of the Zagros (6 - 12 km) has maintained complex tectonic history of the region, which represents all stages of development of a basin from a passive continental shelf to a rift. This finally represents various stages of deformation in relation to ophiolite obduction and continental collision. The study area is located in the south and southeastern part of Iran in the range of 28 and 29 to 55 and 57. The study area includes Hormozgan and Kerman Provinces in national classification. Geographic position of this region at the intersection of three sedimentary structural zones of Zagros, Makran and Central Iran has revealed that Hormozgan Province has specific geological and structural features. Nowadays, remote sensing techniques and particularly structural analysis with satellite images are supplement to the observation and field interpretation. Landsat satellites can be noted in this regard, which has helped the scientists to interprete natural science since a long time ago. Landsat 8 is equipped with panchromatic band and thus has a high spatial resolution. Therefore, the images obtained from this satellite are used. The images are raw and after application of various filters and image processing operations by ER mapper and Arc GIS the lineaments that have remained unidentified are observed. The discoveries are then introduced to the realm of construction geology in the form of a new map of regional faults using the remote sensing technologies.展开更多
文摘采用Gleeble-1500D热模拟试验机,在变形温度为900~1250℃、应变速率为0.001~1 s^-1的条件下对铸态ER8车轮钢进行热压缩试验,得到真应力-真应变曲线。结果发现:其真应力-真应变曲线符合动态再结晶型软化机制,变形初始阶段,材料发生硬化,真应力快速增加,随着变形的继续,材料发生动态回复,加工硬化速率减缓;在材料变形过程中,材料畸变的应变储存能增加,动态再结晶激活,真应力迅速降低,后硬化及软化达到动态平衡。并分析了变形温度和应变速率对该材料高温下真应力的影响,发现真应力的大小随着变形温度的升高及应变速率的降低而减小。通过对试验数据的归纳整理得出,铸态ER8车轮钢的热变形激活能为258.4 k J·mol^-1。建立了Arrhenius双曲正弦本构方程,用作图法求解加工硬化速率,找出峰值应变及临界应变,基于此建立动态再结晶体积分数模型。其能精准地预测此材料的高温软化行为,为有限元数值模拟提供了理论基础。
文摘Zagros orogenic belt has developed on northern-eastern edge of Arabian plate from Northern-Western-Southern-Eastern Turkey to Strait of Hormuz with a length of over 2000 km. Thick sedimentary series of the Zagros (6 - 12 km) has maintained complex tectonic history of the region, which represents all stages of development of a basin from a passive continental shelf to a rift. This finally represents various stages of deformation in relation to ophiolite obduction and continental collision. The study area is located in the south and southeastern part of Iran in the range of 28 and 29 to 55 and 57. The study area includes Hormozgan and Kerman Provinces in national classification. Geographic position of this region at the intersection of three sedimentary structural zones of Zagros, Makran and Central Iran has revealed that Hormozgan Province has specific geological and structural features. Nowadays, remote sensing techniques and particularly structural analysis with satellite images are supplement to the observation and field interpretation. Landsat satellites can be noted in this regard, which has helped the scientists to interprete natural science since a long time ago. Landsat 8 is equipped with panchromatic band and thus has a high spatial resolution. Therefore, the images obtained from this satellite are used. The images are raw and after application of various filters and image processing operations by ER mapper and Arc GIS the lineaments that have remained unidentified are observed. The discoveries are then introduced to the realm of construction geology in the form of a new map of regional faults using the remote sensing technologies.
