SOLUBILITY OF Ca IN Mn AND INTERACTION COEFFICIENTS OF Al AND Fe ON Ca IN Mn AT 1350℃

Solubility of Ca in manganese and manganese alloys was measured under sealed conditions at1350℃.The interaction coefficients of Al and Fe on Ca in Mn were evaluated with the exper-imental data.The standard free energy of liquid Ca in liquid Mn based on the 1 wt-% solu-tion standard was estimated as well.     

THERMODYMICS OF Mn-C-j MELTS AT 1350℃

测定了不同温度下碳在Mn液中的溶解度和碳在Si Mn合金液中1350℃的溶解度。同时又测定了1350℃ Ca在CaC_2坩埚内Mn-C合金液的溶解度。利用实验数据求出e_C~(Si),e_C~C,e_C~(Ca)及Inγ_C~0,并计算出碳在Mn液中的标准溶解自由能及其与温度的关系式。     

Ca在金属Mn中的溶解度及Al,Fe对Mn溶液中Ca的活度系数的影响

本文测定了1350℃时液态金属Ca在纯Mn液中和Mn合金溶液中的溶解度,并计算出Mn液中Al及Fe对Ca的活度相互作用系数。实验结果表明Al对Ca有很强的相互作用,使Ca的溶解度增加,而Fe却使Ca的溶解度下降。本文还就液态Ca溶于Mn液的标准溶解自由能进行了估算。     

THERMODYNAMICS OF TERNARY Fe-B-Si MELTS AT 1450℃ Ⅱ. ACTIVITY OF B AND ITS INTERACTION COEFFICIENTS

用逐次逼近法进行三元系Gibbs-Duhem方程积分,由Fe-i-j三元系中已知的lnγ_i的ε-formalism表示式求lnγ_i的ε-formalism表示式的6个常数.用这种方法由本文的第Ⅰ部分实验求得的Fe-B-Si三元系中lnγ_(Si)(1450℃)的数据,求出lnγ_B的表示式中的6个常数: lnγ_B=-2.82,ε_B~B=5.70,ρ_B~B=-2.8 ε_B~(Si)=16.0,ρ_B~(Si)=24.7,ρ_B~(B,Si)=-34.3这种计算方法除lnγ_(Si)的ε-formalism表达式外,无需任何二元系的数据,并保证了ε_B~(Si),ρ_B~(Si)及ρ_B~(B,Si)与Si的相应常数的热力学自洽性.     

THERMODYNAMICS OF TERNARY Fe-B-Si MELTS AT 1450℃ Ⅰ. ACTIVITY OF Si AND ITS INTERACTION COEFFICIENTS

用Ag浴等活度法测定了1450℃下Fe-B-Si三元系熔体的两条等活度线;用Si浓差电池EMF法测定了Ag-Si合金(银浴)的α_(Si).由实验测定结果计算了Si的活度系数及活度交互作用系数,得到 lnγ_(Si)=-3.19,ε_(Si)~(Si)=7.0,ρ_(Si)~(Si)=6.5, ε_(Si)~B=16.0,ρ_(Si)~B=-12.0,ρ_(Si)~(Si,B)=40.8     

EFFECT OF Cr AND Al CONTENT ON THE STACKING FAULT ENERGY IN γ—Fe—Mn ALLOYS

The effects of Cr and Al content were investigated on the stacking fault energy in austenitic Fe-31Mn-(0-7.26)Cr-0.96C and Fe-31Mn-(0-8.68)Al-0.85C alloys by the thermodynamic analysis.The results show that the additions of chromium or aluminum increase the non-magnetic component of the stacking fault energy in the γ-Fe-Mn alloys,and the effect of aluminum is larger than that of chromium.The change in the magnetic entropy caused in the antiferromagnetic transition increases the free energy difference between the γ and ε phases in the γ-Fe-Mn alloys.The effects of chromium and aluminum on the magnetic component were discussed on the basis of the influence of both upon the antiferromagnetic transition in the γ-Fe-Mn alloys.     

DIFFUSION COEFFICIENTS IN α(δ)-PHASE OF Fe-Mn-Si TERNARY SYSTEM AT 1000℃

本工作是测量1000℃下Fe-Mn-Si三元系组元在α(δ)相的扩散系数。不同成分的合金组成扩散偶在1000℃扩散后,测量Mn和Si的成分分布曲线。根据成分分布曲线用Boltzmann-Matano方法求解得出18个成分的扩散系数。结果表明,主扩散系数D_(MnMN)~(Fe)和D_(SiSi)~(Fe)的数值接近,约为10~(-9)cm~2s~(-1)数量级;交叉扩散系数D_(MnSi)~(Fe)和D_(SiMn)~(Fe)的数值比主扩散系数小一个数量级。D_(SiSi)~(Fe)随Si和Mn的成分增加略有增加;Mn的成分对D_(MnMn)~(Fe)的数值影响不大,但随Si的成分增加而增加。     

AN INVESTIGATION OF RESIDUAL STRESS OF OXIDE SCALE AFFECTED BY THE ADDITION OF RARE EARTH ELEMENTS IN Fe-Cr-Al ALLOY AT 1200 AND 1350℃

本文用衍射仪内标法测定了氧化层的残余应力,研究了稀土元素对Fe-Cr-Al合金在1200℃和1350℃氧化时氧化层残余应力的影响,结果表明,氧化层都存在残余压应力,且稀土元素有明显的影响,不加稀土的A合金σ<100 kgf/mm~2,加(La+Ce)的B合金σ>200kgf/mm~2,加Y的C合金σ>300kgf/mm~2. 若以〔P〕_A=P_(0001)+P_(0118)+P_(1129)+P_(10110)的织构系数值表示氧化层的择优取向的程度,发现氧化层的择优取向程度与粘附性有一定的关系,〔P〕_A>6.5的氧化层不发生剥落,〔P〕_A<6.5的氧化层发生剥落,稀土元素增强氧化层的择优取向程度是它改善氧化层粘附性的原因之一.     

BEHAVIOR OF CERIUM IN GRAIN BOUNDARY SEGREGATION AND ITS INFLUENCE ON EQUILIBRIUM SEGREGATION OF PHOSPHORUS AT GRAIN BOUNDARIES IN α-IRON

用TEM+EDAX和AES方法研究了Fe-0.3％P-0.16％Ce和Fe-0.3％P合金Ce和P的晶界平衡偏聚及Ce对P平衡偏聚的影响,并且对合金的脆性做了研究.结果表明,Fe-0.3％P-0.16％Ce合金晶界有Ce和P的共偏聚,磷的平衡偏聚量不低于Fe-0.3％P合金,但是脆性却由于Ce的偏聚而显著改善.本文从界面二维相的观点讨论了Ce和P在晶界的相互作用.     

FORMATION ENERGIES OF POINT DEFFECTS AND HELIUM－VACANCY CLUSTERS IN γ－Fe

利用分子静力学计算了γ-Fe中的空位(V)、自间隙原子(SIA)、间隙氦原子(HeI)和氦-空位(He-V)团簇的形成能.Fe-Fe,Fe-He和He-He原子间相互作用分别用修正嵌入原子法(MEAM)、Wilson-Johnson势和Beck势来描述.计算结果表明,SIA<100>形成能远小于α-Fe中的SIA<110>形成能,HeI在γ-Fe中的四面体间隙位最稳定.团簇HenV0,HenV1,HenV2和HenV3中的He原子数n分别达到2,5,9和11时即可形成Frenkel对来实现自捕陷,实现自捕陷时的He/V个数比不是定值,且随空位数的增加有逐渐下降趋势.