tailieunhanh - Báo cáo hóa học: " The rate sensitivity and plastic deformation of nanocrystalline tantalum films at nanoscale"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: The rate sensitivity and plastic deformation of nanocrystalline tantalum films at nanoscale | Cao et al. Nanoscale Research Letters 2011 6 186 http content 6 1 186 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access The rate sensitivity and plastic deformation of nanocrystalline tantalum films at nanoscale Zhenhua Cao1 2 Qianwei She1 2 Yongli Huang3 Xiangkang Meng1 2 Abstract Nanoindentation creep and loading rate change tests were employed to examine the rate sensitivity m and hardness of nanocrystalline tetragonal Ta films. Experimental results suggested that the m increased with the decrease of feature scale such as grain size and indent depth. The magnitude of m is much less than the corresponding grain boundary GB sliding deformation with m of . Hardness softening behavior was observed for smaller grain size which supports the GB sliding mechanism. The rate-controlling deformation was interpreted by the GB-mediated processes involving atomic diffusion and the generation of dislocation at GB. Introduction Much research interest has been focused on uncovering the novel plastic deformation mechanisms of nanocrystalline NC metals over the last two decades 1-5 . As the average grain size d decreases to less than 100 nm grain boundary GB -mediated processes such as GB diffusion and sliding become increasingly more important during plastic deformation 6 . Molecular dynamic simulation 1 bubble raft model 2 and experimental results 3 suggested that the corresponding critical d of NC Cu and Ni for softening behavior is below 20 nm. In contrast the other experimental observations suggest that the strength induced by dislocation activation still increases even if d decreases to 20 nm 7 8 . So far the dominant deformation mechanism of NC metals has not been clear yet. Strain rate sensitivity m is an important dynamic parameter for understanding the plastic deformation of polycrystalline metals. In general NC metals show a higher m than that of coarse grain CG and ultrafine grain UFG counterparts due to the .

TÀI LIỆU LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.