Grain Growth Behavior of 5Cr21Mn9Ni4N Steel Micro-Alloyed by Rare Earth

Grain growth behavior of 5Cr21Mn9Ni4NRE steel was experimentally studied at various solid solution treatment temperatures and holding for different times. The experimental results show that the 5Cr21Mn9Ni4NRE steel has the feature of sharp austenite grain coarsening after solid solution treatment at the temperature above 1150 ℃. RE added in the steel has the benefit to restrain grain growth and increase grain growth activation energy.

Morphological evolution and growth kinetics of Kirkendall voids in binary alloy system during deformation process-Phase field crystal simulation study

The formation and growth of Kirkendall voids in a binary alloy system during deformation process were investigated byphase field crystal model.The simulation results show that Kirkendall voids nucleate preferentially at the interface,and the averagesize of the voids increases with both the time and strain rate.There is an obvious coalescence of the voids at a large strain rate whenthe deformation is applied along the interface under both constant and cyclic strain rate conditions.For the cyclic strain rate appliedalong the interface,the growth exponent of Kirkendall voids increases with increasing the strain rate when the strain rate is largerthan1.0×10-6,while it increases initially and then decreases when the strain rate is smaller than9.0×10?7.The growth exponent ofKirkendall voids increases initially and then decreases gradually with increasing the length of cyclic period under a square-waveform constant strain rate.

Deposition pressure effect on the surface roughness scaling of microcrystalline silicon films

The scaling behaviour of surface roughness evolution of microcrystalline silicon （/zc-Si：H） films prepared by very- high frequency plasma-enhanced chemical vapour deposition （VHF-PECVD） has been investigated by using a spectroscopic eHipsometry （SE） technique. The growth exponent β was analysed for the films deposited under different pressures Pg. The results suggest that films deposited at Pg = 70 Pa have a growth exponent β about 0.22, which corresponds to the definite diffusion growth. However, abnormal scaling behaviour occurs in the films deposited at Pg = 300 Pa. The exponent β is about 0.81 that is much larger than 0.5 of zero diffusion limit in the scaling theory. The growth mode ofμc-Si：H deposited at Pg = 300 Pa is clearly different from that of μc-Si：H at Pg = 70 Pa. Monte Carlo simulations indicate that the sticking process and the surface diffusion of the radicals are two key factors to affect the growth mode under different pressures. Under Pg = 300 Pa, β〉 0.5 is correlated with the strong shadowing effect resulting from the larger sticking coefficient.

On Asynchronous Exponential Stability of C_0 Semigroups

A C 0 semigroup T (t) in Banach space is called to have asynchronous exponent growth with intrinsic growth constant λ 0 if there exists a nonzero finite rank operator P in X such that lim t→∞T (t) = P. Characteristic conditions are established in Hilbert space for T (t), to have asynchronous exponent growth.