Ti-Nb-V钢中第二相粒子对焊接HAZ晶粒度及韧性影响的价电子结构分析

基于"固体与分子经验电子理论"(EET),利用合金相和相界面的价电子结构参数统计值n′A、E′A、Δρ′、σ分析第二相粒子和固溶Nb对焊接HAZ组织和韧性的影响。结果表明:Nb元素固溶时,因Δρ′/σ值大于其他合金元素而使Nb具有强烈阻碍奥氏体晶界迁移的作用;第二相粒子Ti(V、Nb)C(N)析出时,形成相界面的Δρ′/σ较大,因而更能有效地钉扎奥氏体晶界而使高温奥氏体晶粒显著细化;第二相粒子析出后,能够促进新相铁素体生成,改善焊接HAZ韧性的机理也可追溯到n′A、E′A及Δρ′。上述分析结果与实验结果符合很好。

Valence electron structures analysis for effect of second phase particles on grain size and toughness of weld heat affected zone in Ti-Nb-V steel

Based on the the empirical electron theory of solids and molecules(EET),the effects of second phase particles andsolution Nb element on the microstructure and toughness were analysed with the use of valence electron structure parametersn′A,E′A,Δρ′ and σ of phase and phase interfaces. The results show that the larger ratio of Δρ′/σ causes the solution element Nb togenerate intense hindering effect for the migration of austenite grain boundary;While second phase particles with much largerΔρ′/σ will generate obvious pinning effect for austenite grain boundary,resulting in refinement of austenite grain size;Theacceleration in the formation of ferrite as well as the improvement in toughness of HAZ,generated by the precipitation of secondphase particles,can also be traced to the electron structure parametersn′A,E′Aand Δρ′. The above analysed results agree wellwith the experimental ones.