20g钢珠光体球化后拉伸断裂过程组织变化

Microstructural Characterization of Pearlite Spheroidized 20g Steel During Tensile Deformation

采用现场金相显微镜对珠光体球化的20g钢拉伸过程进行了原位观察,用扫描电镜分析变形组织及裂纹。结果表明:珠光体发生球化的20g钢在拉伸过程中,在某些晶粒内部首先发生变形,产生大量的滑移带,并在晶界处产生塞积。随后其它部分晶粒转动,形成对变形有利的取向,各晶粒协调变形。拉伸过程中,裂纹首先产生于试样边缘的珠光体组织。试件内部,微裂纹空洞在铁素体和珠光体的晶界处萌生,由于应力集中,产生扩展连接,呈穿晶和沿晶断裂。

The microstructure of pearlite spheroidized 20g steel during tensile deformation was investigated with field metalloscope. SEM images of the specimen were taken after deformation. The results show that during tensile deformation, pearlite spheroidized 20g steel got deformed in some of its grains. It causes a large amount of glide bands, and piles-up at the grain boundary. Some of other grains start to deform, which form favorable orientation in order to complete further deformation. During tensile deformation, microeracks generate at the pearlite on the edge of the specimen. Microscopic voids generated at the ferrite and pearlite grain boundary inside the specimen, then extend and connect to microeracks, it shows as transcrystalline and intercrystalline fracture.