铸态铁镍基耐蚀合金热压缩模拟研究

通过热模拟压缩试验,得到了温度为900~1200℃(温度间隔为50℃)、应变速率为0.1 s-1、应变量为35%条件下时效强化型铁镍基耐蚀合金的应力-应变曲线。不同温度对试验合金的热压缩应力-应变曲线有较大影响。随着变形温度的提高,峰值压缩应力逐渐减小,并且降低的幅度由急变缓。试验后样品的硬度也随变形温度的提高而降低。试验后样品的显微组织均几乎保留着原有的铸态组织形貌,呈明显树枝晶,当试验温度较低时,再结晶程度很小,随着温度的提高,再结晶变得更明显,细小的再结晶晶粒有所增加,但远没有达到完成的地步。当温度为1150和1200℃时,显微照片上可见明显的沿晶裂纹,可能与试验温度过高有关,也可能与单道次变形量太大有关。

Study on hot compression test for as-cast Fe-Ni based corrosion-resistant alloy

The stress-strain curves of aging-strength Fe-Ni based corrosion-resistant alloy were obtained by the hot compression test under conditions of temperature 900-1200 ℃ (50 ℃ increments per test),strain rate 0.1 s-1 and strain 35％.The stress-strain curves vary greatly at different temperature.The peak compression stress decreases gradually with the increase of temperature,and the decreasing tendency is gradually retarded.After testing,the hardness of samples also decreases with the increase of temperature,however,the microstructure keeps its original cast structure with dendrite.When the test temperature is lower,the recrystallization grain is smaller,and it is more obvious with increasing temperature.Therefore,the tiny recrystallization grain increases,and the recrystallization fraction is far from the complete recrystallization.When test temperatures are 1150 and 1200 ℃,intergranular cracks are found in the micrograph,and it is related to over high temperature or over large single-stroke deformation.