过共析钢温变形过程中的组织演变 Ⅱ.渗碳体的球化及Al的影响

MICROSTRUCTURE EVOLUTION OF HYPEREUTECTOID STEELS DURING WARM DEFORMATION Ⅱ.Cementite Spheroidization and Effects of Al

利用Gleeble 1500热模拟试验机进行单轴热压缩实验,研究了合金元素Al的添加对过共析钢等温球化及温变形过程中渗碳体球化及所得超细(α+θ)复相组织的影响.结果表明:等温球化时,Al的添加使过共析钢获得较细小的渗碳体颗粒与较小铁素体晶粒的复相组织;在温变形过程中,合金元素Al能够阻碍Fe和C原子的扩散,减缓片层渗碳体的熔断球化及渗碳体粒子的粗化,抑制渗碳体粒子在铁素体内部的再析出,获得超细(α+θ)复相组织.

The effects of Al on the spheroidization of cementite and the formation of ultrafine （α＋θ） microstructure of hypereutectoid steel during isothermal spheroidizing and warm deformation were investigated by uniaxial hot compression simulation experiment. The results indicate that during isothermal spheroidizing, the fine grained cementite particles and ferrite are obtained by addition of Al. Ultrafinc （α＋θ） microduplex microstructures can be formed by warm deformation in a very short time. During warm deformation, the diffusion of carbon and iron atoms are impeded with the addition of Al, the spheroidization of lamellar cementite and the coarsening of cementite particles are retarded. And the re-precipitation of cementite particles in ferrite matrix is also restricted, resulting in a more ultrafine （α＋θ） microduplex microstructure.