高强TRIP钢的动态力学性能

Dynamic mechanical properties of high strength TRIP steel

  • 摘要: 将Si-Mn系双相钢(DP钢)作为对比钢种,分析研究了高应变速率下600 MPa级Si-Mn系TRIP钢及含Al、Ni的1000 MPa级TRIP钢的显微组织及其动态力学性能.对DP钢而言,其抗拉强度随着应变速率的增大而升高,断裂延伸率则由于绝热温升的作用也呈上升趋势;对TRIP钢而言,随着应变速率的增大,其抗拉强度不断增大,断裂延伸率先减小后增大,但无法达到其静态拉伸时的塑性水平,这是由于在动态拉伸条件下奥氏体向马氏体的渐进式转变被抑制造成的.此外,在相同应变速率下测得的TRIP钢的绝热温升始终比DP钢高,而这部分高出的热量应当来自于在动态变形条件下TRIP钢中发生TRIP效应后释放的相变潜热.

     

    Abstract: Using Si-Mn dual-phase (DP) steel as a reference, the microstructural evolution and dynamic mechanical properties of Si-Mn transformation-induced plasticity steel (TRIP) steel at the 600 MPa level and TRIP steel offering the ultimate tensile strength (UTS) level up to 1000 MPa containing Al and Ni were investigated under high strain-rate deformation. It is found that the tensile strength increases with increasing strain rate and the fracture elongation increases due to adiabatic heating in the DP steel. In the TRIP steel, the tensile strength increases with increasing strain rate while the fracture elongation decreases at first and then increases. However, the ductility of the TRIP steel is relatively low at high strain rate since the gradual transformation effect of retained austenite is inhibited. The adiabatic heat produced during high strain-rate deformation is higher in the TRIP steel than in the DP steel, and it is suggested that this extra heat originates from the latent heat of martensitic transformation in the TRIP steel during dynamic deformation.

     

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