3D atomistic simulation of fatigue behaviour of cracked single crystal of bcc iron loaded in mode III

We present new results of 3D molecular dynamic (MD) simulations of a mechanical behaviour of an edge crack $(\overline{1}10)$ [1 1 0] (crack plane/crack front) in a single crystal of bcc iron cyclically loaded in mode III at room temperature. Our previous 3D molecular dynamic simulations showed that this crack under monotonic uniaxial tension loading in mode I emitted blunting dislocations in the inclined $〈1\overline{1}1〉\{\overline{1}12\}$ slip systems and it was stable up to very high loads, in qualitative agreement with experiments and continuum predictions. Our question is how the cyclic loading in mode III changes the crack behaviour and its stability. The paper also brings information on how the distribution of external forces in mode III influences the fatigue crack behaviour and how the defects generated by the crack can produce experimentally observed advances of the crack front in local modes I, II, I + II and II + III.     

Vapor Pressures of Platinum,Iridium, and Rhodium

The vapor pressures of platinum, iridium, and rhodium have been measured using a microbalance technique based on the Langmuir method. Heats of sublimation at 298 °K were calculated with the aid of free energy functions. The least square lines for the vapor pressure data, the heats of sublimation, and the normal boiling points obtained were as follows:

1. Platinum: LogPatm=6.761−27,575T(1,916to2,042°K)ΔHs°(298)=134.9±1.0kcal/molebp=4,100±100°K
2. Iridium: LogPatm=7.139−33,337T(1,986to2,260°K)ΔHs°(298)=159.9±2.0kcal/molebp=4,800±100°K
3. Rhodium: LogPatm=6.894−27,276T(1,709to2,075°K)ΔHs°(298)=132.5±2.0kcal/molebp=4,000±100°K.

The indicated uncertainties are estimates of the overall limits of error. The value of the gas constant R used in the calculation of ΔHs° is 1.98726 cal/degree mole.     

Heats of Hydrolysis and Formation of Potassium Borohydride

The heat of reaction of potassium borohydride with 0.060 molal HCl has been measured by solution calorimetry. The heat of solution of the hydrolysis products has also been measured and combined with certain literature values to calculate the process: KBH4(c)+HCl(g)+3H2O(liq)→KCl(c)+H3BO3(c)+4H2(g),ΔH°(25°C)=−354.06±1.84kj/mole(−84.62±0.44kcal/mole).A combination of this value with literature values for the heats of formation of HCl(g), H₂O(liq), KCl(c), and H₃BO₃(c) gives for KBH₄(c): ΔHf°(25°C) = ?228.86 ± 2.30 kj/mole(?54.70 ± 0.55 kcal/mole).Other data on the heats of formation of the alkali-metal borohydrides are discussed briefly.     

Heat of Formation of Beryllium Chloride

The heat of formation of beryllium chloride has been determined, by the direct combination of the elements in a calorimeter, according to the process, Be(c)+Cl2(g)=BeCl2(c),ΔH°(25°C)=−493.85±2.35kj/mole,=−118.03±0.56kcal/mole.The data obtained by other investigators are discussed briefly.     

Heat of Formation of N-Dimethylaminodiborane

The heat of reaction of N-dimethylaminodiborane with water has been determined according to the reaction: (CH3)2NB2H5(g)+6H2O(liq)=(CH3)2NH(g)+2H3BO3(c)+5H2(g),ΔH(25°C)=−374.99±2.71kj/mole=−89.62±0.65kcal/mole.A combination of this value with the heat of vaporization, and with the heats of formation of boric acid, dimethylamine, and water gives for liquid N-dimethylaminodiborane: ΔHf°(25 °C) = ?36.22 ± 0.75 kcal/mole.     

Heats of Hydrolysis and Formation of Dimethoxychloroborane

The heat of hydrolysis of dimethoxychloroborane has been measured; for the reaction, (CH3O)2BCl(liq)+3H2O(liq)=H3BO3(c)+2CH3OH(liq)+HCl(g)ΔH(25°C)=−26.6±0.8kj/mole=−6.4±0.2kcal/mole.From this, we have calculated the heat of formation of dimethoxychloroborane: for the liquid, ΔHf° (25 °C) = −782.1 ± 1.8 kj/mole (−186.9±0.4 kcal/mole), and for the gas, ΔHf° (25 °C) = −747.9 ±2.2 kj/mole (−178.8±0.5 kcal/mole).     

Heats of Formation of Lithium Perchlorate,Ammonium Perchlorate,and Sodium Perchlorate

Calorimetric measurements of the heats of solution of LiClO₄(c), NH₄ClO₄(e), and NaClO₄(c) have been made. The results have been combined with the heats of formation of KClO₄(c), KCl(c), LiCl(c), NH₄Cl(c), and NaCl(c), to obtain the following heats of formation: LiClO4(c),ΔHf°(25°C)=−380.27±1.21kj/mole=−90.89±0.29kcal/mole,NH4ClO4(c),=−295.98±1.35kj/mole=−70.74±0.32kcal/mole,NaClO4(c),=−382.75±0.93kj/mole=−91.48±0.22kcal/mole.A brief summary of other recent data has been included.     

Franck-Condon Factors to High Vibrational Quantum Numbers I: N2 and [... formula ...]

Franck-Condon factor arrays have been computed numerically to high vibrational quantum numbers for the band systems N2:C3II−B3II(Second Positive)N2:B3II−A3∑(First Positive)N2:A3∑−X1∑(Vegard Kaplan)N2:a1II−X1∑(Lyman-Birge-Hopfield)N2+;A2II−X2∑(Meinel)N2+:B2∑−X2∑(First Negative)and for the following ionization transitions N2X1∑→N2+X2∑N2X1∑→N2+A2IIN2X1∑→N2+B2∑