热作模具钢淬火回火态的内耗谱分析

对热作模具钢淬火后回火态试样的内耗谱进行了分析.研究表明，淬火态试样的内耗谱由3部分构成.其中：157.2 °C处的内耗峰是由于体心立方结构的马氏体晶格畸变引起应力感生碳原子微扩散的结果；225.5 °C处为溶质原子与位错交互作用产生的SKK峰及其背景内耗峰.随着回火温度升高，SKK峰的弛豫强度逐渐减小，此时，碳原子与部分合金元素以碳化物形式结合而从基体中析出，使得其晶格畸变减弱，157.2 °C处的内耗峰消失；部分碳化物在位错处形核并使位错段增长、弛豫时间增大；内耗峰位置的移动主要归因于合金元素与碳原子的作用.

Analysis on Internal Friction in Quenched and Tempered Hot Work Steel

The internal friction spectrum of hot die steel Dievar with quenched into oil and tempered at different temperature was studied. The internal friction spectrum is decomposed into two peaks and background internal friction for quenched steel. One peak is attributed to stress induced micro diffusion of carbon in martenstic alloy steel at 157.2 °C. The 225.5 °C peak named SKK peak is related to the interactions between carbon atoms and dislocations. When the mount of carbon in solid solution is reduced by tempering the specimen at an elevated temperature, the height of the peak lowers and the peak shifts to a higher temperature. Some carbides nucleate and grow at dislocations, which induces stress relaxation. Relaxation time increases by the length of dislocation growed. The movement of the internal friction peak position is attributed to the effects of alloying elements and carbon atoms.