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中碳钢回火马氏体热变形过程中的铁素体动态再结晶李龙飞1,夏杨青1,孙祖庆1,杨王玥2(1.北京市北京科技大学新金属材料国家重点实验室2.北京科技大学材料科学与工程系,北京100083)摘 要:利用热压缩实验,研究了中碳钢回火马氏体在700℃/0.01 s-1条件下变形时的组织演变规律,分析了渗碳体粒子状态的影响.实验结果表明:中碳钢回火马氏体热变形过程中,发生了渗碳体粒子粗化和铁素体动态再结晶,形成由微米级的等轴铁素体晶粒与均匀分布的渗碳体粒子组成的超细化(α+θ)复相组织.与静态回火相比,形变促进Fe原子和C......
and white phases, which indicate β phase (black) as well as hydride δ (black) and α phase after eutectoid reaction βH→α+δ. Fig.1 Microstructures of Ti6Al4V alloy hydrogenated at 750 ℃: (a) 0.0% H; (b...″ and the eutectoid reaction βH→α+δ happen when hydrogenated at 750 ℃ for 1 h followed by air-cooling to room temperature. Additionally, the β peaks move to lower angles gradually with the increase of hydrogen......
eutectic and eutectoid reactions are occurred. L→Nb+Nb3Si Nb3Si→Nb+Nb5Si3 Fig.2 SEM image of as-casting Nb-18.7%Si alloy Fig.3 Binary Nb-Si phase diagram under rapid solidification In the case... reaction. L→Nb+Nb3Si From above, it can be known that Nb3Si phase in the as-casting sample do not change into the eutectoid structure of Nb+Nb5Si3. MENDIRATTA et al[11], BEWLAY et al[12, 13......
shape memory alloy (Cu-11Al-5Mn and Cu-11Al-5Mn-Re) is nearly above an order of magnitude compared to the Cu-Al alloy. When adding Mn element to Cu-Al binary alloy, the eutectoid transformation... ℃, eutectoid γ2 generates from the intracrystalline granular precipitation and eutectoid α has become matrix. Moreover there are the bead-chain first eutectoid γ2 on the grain boundaries. And some......
; Engineering A, 1992, 158: 93-99. [11] ZHU Y H. Milling induced microstructural change in furnace cooled eutectoid Zn-Al alloy [J]. Journal of Materials Processing Technology, 1997, 63: 624-629. [12] ZHU Y H... changes in as-cast eutectoid Zn-Al alloy [J]. J Mater Sci, 1994, 29: 1549-1555. [16] ZHU Y H. Structural evolution in mechanically milled eutectoid Zn-Al based alloy [J]. Z Metallkde, 1997, 88......
was at (821±2) K. The maximum solid solubility of Mg in dHCP (Nd) was determined by JOSEPH and GSCHNEIDNER[4] to be at 8.2%Mg (mole fraction) at the eutectoid decomposition temperature... equilibria by optical or SEM micrographs. The Mg-rich eutectic temperature, the eutectoid decomposition temperature of BCC_A2 and the maximum solid solubility of Mg in dHCP show good agreement......
states. The equilibrium phase diagram predicts that, microstructure of the studied alloys should be made up of γ2 phase and the (α+γ2) eutectoid phase, but in reality, microstructure of the as-cast alloys consisted of α phase, β′ phase, γ2 phase, (α+γ2) eutectoid and the κ phase, as shown in Fig.5(a), XRD analysis by different authors reported the same results[2,3,13]. Light areas are α phase......
of alloy used in present study. The mold temperature of 270 ℃ is close to the temperature of an eutectoid transformation of the used alloy, 277 ℃. The fine precipitations begin to appear at the temperature of eutectoid transformation. This is likely to be benefit for the form filling. Fig.7 Phase diagram of Zn-Al alloy[17] Fig.8 shows the maximum aspect ratio of the microwires in different......