Indentation Creep of Molybdenum: Comparison Between Thin Film and Bulk Material

1994 ◽  
Vol 356 ◽  
Author(s):  
K. B. Yoder ◽  
D. S. Stone ◽  
J. C. Lin ◽  
R. A. Hoffmann
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Room Temperature ◽  
Bulk Material ◽  
High Hardness ◽  
Rate Sensitivity ◽  
Indentation Creep ◽  
Creep Properties ◽  
Measurement Path ◽  
Arc Evaporation

AbstractIndentation creep, load relaxation, and rate-change experiments probe room temperature and 80°C creep properties of a 1.3 μm-thick molybdenum film on silicon. The film, with 0.51 GPa compressive stress, 8 GPa hardness and estimated 40 nm grain size, was deposited using steered-arc evaporation at -17V bias. Despite its small grain size and high hardness, the thin film behaves like bulk molybdenum does: the rate sensitivity of the hardness is only weakly-dependent on measurement path (as with bulk material), and activation volumes calculated based on strain rate sensitivity are consistent with those of bulk molybdenum We suspect deformation mechanisms are similar to those in bulk molybdenum under similar conditions.

Effects of Annealing on Microstructure and Mechanical Properties of Bulk Nanocrystalline Fe3Al Based Alloy with 10 Wt. % Mn Prepared by Aluminothermic Reaction

2011 ◽  
Vol 236-238 ◽  
pp. 1939-1944
Author(s):  
Pei Qing La ◽  
Xin Guo ◽  
Yang Yang ◽  
Chun Jie Cheng ◽  
Xue Feng Lu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Annealed Alloy ◽  
Creep Properties ◽  
Aluminothermic Reaction ◽  
Microstructure And Mechanical Properties ◽  
Bulk Nanocrystalline ◽  
Hot Rolled

Microstructure and mechanical properties of bulk nanocrystalline Fe3Al based alloy with 10 wt. % Mn prepared by aluminothermic reaction after annealing at 600, 800 and 1000°C for 8 h were investigated in order to gain insights in effects of annealing. Crystal structure of the alloy did not change and a fiber phase with enriched Mn appeared in the annealed alloy. Grain size of the alloy changed a little after annealing at 600°C but increased a lot after annealing at 800 and 1000°C. The annealed alloy had plasticity in compression at room temperature and the alloy annealed at 1000°C had yield strength of 782 MPa. The alloy without annealing has creep properties in compression at 800 and 1000°C and can be easily hot rolled to strip and sheet.

Physical properties of spinel iron oxide thin films

1988 ◽  
Vol 3 (2) ◽  
pp. 344-350 ◽  
Author(s):  
C. Ortiz ◽  
G. Lim ◽  
M. M. Chen ◽  
G. Castillo
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Size ◽  
Physical Properties ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Infrared Transmission ◽  
Transmission Properties ◽  
Annealing Conditions ◽  
Deposition Conditions

This paper describes the complexity of the spinel iron oxides in thin-film configuration. First, the experimental deposition conditions are determined for the parameters of substrate temperature and oxygen flow such that only the “Fe3O4” phase is formed. Then a study is made of how the structural (grain size, lattice parameter, texture), magnetic (M), and optical (visible and infrared transmission) properties of the films depend on the deposition and postdeposition (air annealing) conditions. The experimental deposition region is defined where the films have the most similar physical properties to bulk Fe3O4 and subsequently, after annealing, to bulk gamma Fe2O3. Finally, a discussion is presented of a model that accounts for the anomalous, low values of the magnetic moment for the samples deposited at room temperature. The model proposes an overpopulation of the iron tetrahedral A sites.

Formation of Metal Nitrides by Nitrogen Implantation

1985 ◽  
Vol 54 ◽  
Author(s):  
En Ma ◽  
Bai-Xin Liu ◽  
Xin Chen ◽  
Heng-De Li
Keyword(s):  
Thin Film ◽  
Systematic Study ◽  
Room Temperature ◽  
Bulk Material ◽  
Ion Beam ◽  
Phase Identification ◽  
Metal Nitrides ◽  
Nitrogen Implantation ◽  
X Ray ◽  
Nitride Formation

ABSTRACTA systematic study was performed to investigate the ion beam induced metal nitride formation by direct nitrogen implantation into 10 selected metals, either of thin film or bulk material. An X-ray diffractometer, together with a specially-designed Seemann-Bohlin attachment, was employed to provide fast and reliable phase identification in the thin implanted layer. The results show that room temperature nitrogen implantation can lead to the formation of many, but not all, of the equilibrium metal nitrides. The formation of metal nitrides by implantation is discussed in terms of the thermodynamic condition and the readiness of structural trans format ion.

Strain Rate Sensitivity of Ultrafine Grained FCC- and BCC-Type Metals

2006 ◽  
Vol 503-504 ◽  
pp. 781-786 ◽  
Author(s):  
Johannes May ◽  
Heinz Werner Höppel ◽  
Matthias Göken
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Testing Temperature ◽  
Ultrafine Grain ◽  
Ultrafine Grain Size ◽  
Ultrafine Grained

The dependence of the strain rate sensitivity (SRS) of α-Fe and Al 99.5, as typical representatives of fcc- and bcc-type metals, on the testing temperature and with respect to the microstructure is investigated. In particular, the differences between conventional grain size (CG) and ultrafine grain size (UFG) are pointed out. UFG Al 99.5 generally shows an elevated SRS compared to CG Al 99.5. In case of α-Fe the SRS of the UFG state is decreased at room temperature, but increased at 200 °C, compared to the CG state. It is shown that the SRS also influences the ductility of UFG-metals in tensile tests.

SUPERPLASTIC INDENTATION CREEP OF FINE-GRAINED Sn-1% Bi ALLOY

2008 ◽  
Vol 22 (18n19) ◽  
pp. 2823-2832 ◽  
Author(s):  
REZA MAHMUDI ◽  
H. MHJOUBI ◽  
P. MEHRARAM
Keyword(s):  
Room Temperature ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Indentation Creep ◽  
Fine Grained ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Boundary Sliding ◽  
Power Law Creep ◽  
Conventional Rolling

Creep and superplasticity of the fine-grained Sn -1wt.% Bi alloy, processed by conventional rolling (CNR), cryorolling (CRR) and equal channel angular pressing (ECAP) routes, were investigated by indentation testing at room temperature (T > 0.6T m ). Based on the steady-state power law creep relationship, the stress exponents of 4.1, 2.8 and 2.5 were obtained for the CNR, CRR and ECAP routes, respectively. The corresponding strain rate sensitivity (SRS) indices of 0.24, 0.36 and 0.40, corresponding respectively to the grain sizes of 2.8, 2.1 and 1.2 μm, indicate that the materials processed by ECAP and CRR exhibit superplastic deformation behavior for which, grain boundary sliding is the possible creep mechanism.

Mechanical Properties of Thin Film Aluminum Fibers: Grain Size Effects

1990 ◽  
Vol 188 ◽  
Author(s):  
James E. Steinwall ◽  
H. H. Johnson
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Size Effects ◽  
Rate Sensitivity ◽  
Deformation Mechanisms ◽  
Grain Sizes ◽  
Diffusion Controlled ◽  
Mechanical Strengths

ABSTRACTThin film aluminum fibers with grain sizes of 35 and 100 nm were pulled in a microtensile tester. The larger grains led to greater yield and tensile strengths but smaller strains to failure. Both samples had mechanical strengths 3–6 times greater than bulk aluminum. In addition, the small grained fibers had a strain rate sensitivity exponent of 0.26 suggesting diffusion controlled plastic deformation mechanisms.

Influence of grain size on strain rate sensitivity in rolled Mg–3Al–3Sn alloy at room temperature

2013 ◽  
Vol 68 (5) ◽  
pp. 229-232 ◽  
Author(s):  
Hui-Yuan Wang ◽  
En-Song Xue ◽  
Xiao-Long Nan ◽  
Tao Yue ◽  
Yan-Peng Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity

scholarly journals Strain-rate sensitivity of hardness of nanocrystalline Ni75at.%Al25at.% alloy film

2003 ◽  
Vol 18 (2) ◽  
pp. 382-386 ◽  
Author(s):  
A.H.W. Ngan ◽  
J.B. Pethica ◽  
H.P. Ng
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Alloy Film ◽  
Alloy Films ◽  
Grain Sizes ◽  
Room Temperature Strength

Room-temperature indentation experiments carried out on nanocrystalline Ni75at.%Al25at.% alloy films with a range of grain sizes revealed that the strain-rate sensitivity of hardness is nearly zero and that the hardness increases as grain size decreases. The strain-rate insensitivity of hardness indicates that the room-temperature strength of these alloy films is dominated by an athermal, strain-rate-insensitive component. The hardness of the films was found to be in the range of 2.4 to 3.3 GPa, depending on grain size.

Strain Rate Sensitivity Studies of Cryomilled Al Alloy Performed by Nanoindentation

2008 ◽  
Vol 584-586 ◽  
pp. 221-226 ◽  
Author(s):  
Byung Ahn ◽  
R. Mitra ◽  
A.M. Hodge ◽  
Enrique J. Lavernia ◽  
S.R. Nutt
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Bulk Material ◽  
Rate Sensitivity ◽  
Al Alloy ◽  
Cryomilled Powder ◽  
Average Grain Size ◽  
Al 5083 Alloy ◽  
Sensitivity Studies

Al 5083 alloy powder was mechanically milled in liquid nitrogen to achieve a nanocrystalline (NC) structure having an average grain size of 50 nm with high thermal stability, and then consolidated by quasi-isostatic (QI) forging. The consolidation resulted in ultrafine grains (UFG) of about 250 nm, and the bulk material exhibited enhanced strength compared to conventionally processed Al 5083. The hardness of as-cryomilled powder and the UFG material was measured by nanoindentation using loading rates in the range of 50−50,000 /N/s, and results were compared with the conventional grain size alloy. Negative strain rate sensitivity was observed in the cryomilled NC powder and the forged UFG plate, while the conventional alloy was relatively strain rate insensitive.

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