冲击载荷下灰口铸铁力学行为的率效应及其破坏特性

利用ＳＨＰＢ压杆及Ｉｎｓｔｒｏｎ液压伺服材料试验机对灰口铸铁从准静态（应变率１０＾－４ｓ＾－１）列冲击动态（应变率４＊１０＾３ｓ＾－１）进行了宏观与微观相结合的试验研究，得到了该材料在不同应变率下的应力－应变曲线。实验结果表明，灰口帮铁在塑性变形初期对应变率不敏感，随应变增大则具有一定的应变率硬化效应，但在更高应变率下随应变增大会出现反向应变率效应，这些特性与灰口铸铁源于片状石墨处内部微裂纹纹成核

Study on Mechanical Properties of Strain-Rate Effect and its Failure Mode for Cast Iron under Impact Loading

By SHPB method and INSTRON test machine, the mechanical behavior of flaky graphite cast iron was studied in a strain-rate range from 10-4 to 3 x 103 s- 1 and the stress-strain curves was obtained. Results show that the flow stress of this cast alloy appear almost no strain sensitivity at the beginning of plastic deformation, and later appear some rate-hardening effects with development of plastic deformation. Furthermore, at higher strain-rates, flaky graphite cast iron shows negative strain-rate effect This is mainly due to the initiation, enlarging and coalesce of the micro-crack between the flaky graphite and cast alloy base.This internal damage process is also related to rate-dependent evolution.