【摘要】 随 Nb 含量的增加,HP 合金蠕变断裂强度的变化表现出极大值特征。在含碳0.4（wt%）的HP 合金中添加0.5（wt%）以下的 Nb,主要起固溶强化作用;当 Nb 量约1.5（wt%）时,可以获得最佳的蠕变断裂强度。其原因是在共晶组织中形成了形态复杂的共晶 NbC,在晶内析出了高度弥散的二次 NbC,以及由于 Nb 的加入提高了组织稳定性;当 Nb 量进一步提高时,由于共晶 NbC 形成了片层状共晶团以及晶内 M₂₃C₆大量减少使蠕变断裂强度下降。更多还原

【Abstract】 With the increase of Nb content,the change of the creep rupture strength of HP alloy characterizes a peak value.When the Nb content in HP alloy containing 0.4 wt% C is less than 0.5 wt%,the Nb exists in the matrix and mainly plays the part of solution strengthening.With the increase of Nb con- tent the creep rupture strength of the alloy also increases and the optimal str- ength can be obtained when the content reaches about 1.5 wt%.This results from the formation of eutectic NbC carbides on grain boundaries with a com- plicated morphology,the precipitation of fine secondary NbC within grains and microstructure stabilization due to the addition of Nb.When the Nb con- tent exceeds 1.5 wt%,the eutectic NbC carbides on grain boundaries become lamellar and the amount of M₂₃C₆ carbides within grains decrease significan- tly,and therefore the creep rupture strength of the alloy decreases.更多还原