scholarly journals Grain Size Dependent Mechanical Properties in Nanophase Materials

1994 ◽  
Vol 362 ◽  
Author(s):  
Richard W. Siegel ◽  
Gretchen E. Fougere
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Grain Size ◽  
Grain Boundary ◽  
Present Knowledge ◽  
New Materials ◽  
Size Dependent ◽  
Grain Structures ◽  
Nanophase Materials ◽  
Property Changes

AbstractIt has become possible in recent years to synthesize metals and ceramics under well controlled conditions with constituent grain structures on a nanometer size scale (below 100 nm). These new materials have mechanical properties that are strongly grain-size dependent and often significantly different than those of their coarser grained counterparts. Nanophase metals tend to become stronger and ceramics are more easily deformed as grain size is reduced. The observed mechanical property changes appear to be related primarily to grain size limitations and the large percentage of atoms in grain boundary environments. A brief overview of our present knowledge about the grain-size dependent mechanical properties of nanophase materials is presented.

Sintering and Mechanical Properties of Alumina Ceramics Prepared by Nanosize Alumina

2007 ◽  
Vol 544-545 ◽  
pp. 821-824
Author(s):  
Indra ◽  
S.W. Oh ◽  
Hee Joon Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Relative Density ◽  
Mechanical Characteristics ◽  
Indentation Test ◽  
Test System ◽  
Alumina Ceramics ◽  
New Materials ◽  
Size Dependent

This work examined the mechanical properties of alumina that can directly be enhanced by ratio of nano sized alumina powders additives to micro size alumina powders (n/m ratio). These new materials have mechanical properties that are strongly grain size dependent and often significantly different from those of their coarser grained counter parts. The mechanical characteristics of samples were observed by using the indentation test system. This data shows that the relative density for the sample is increased with increasing Meyer hardness.

Research on the Microstructure and Mechanical Property of Ti-7Cu Alloy after Semi-Solid Forging

2016 ◽  
Vol 35 (6) ◽  
pp. 543-550 ◽  
Author(s):  
Yongnan Chen ◽  
Yazhou Huo ◽  
Yongqing Zhao ◽  
Zhiping Sun ◽  
Fan Bai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Grain Size ◽  
Solid State ◽  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Precipitation Behavior ◽  
Semi Solid ◽  
Solid Forging ◽  
Microstructure And Mechanical Property

AbstractThe present work is focused on the development of microstructure of Ti-7Cu alloy as a function of forging temperature and forging ratio in semi-solid state and the influence of resulting microstructure on the mechanical properties. The experimental results showed that the dynamic recrystallization occurred during semi-solid forging and the grain refinement was attained which is considered to be favorable for improving the semi-solid formability. The grain size increased with forging temperature and decreased with forging ratio. Forging temperature has a significant effect on the precipitation behavior in grain boundary regions during the semi-solid processing. More acicular-Ti2Cu tended to precipitate in grain boundary regions with higher forging temperature and finally formed precipitates zones adjacent to grain boundaries after forged at 1,100°C. High ultimate tensile strengths and low elongation have been achieved after semi-solid forging. The strength and hardness decreased with increase of forging temperature, while the ductility increased with increase of forging ratio. The relative contributions of tensile properties were attributed to the varieties of grain size and the distribution of Ti2Cu precipitates obtained by semi-solid forging.

Effect of Post Weld Heat Treatment on Fusion and Heat Affected Zone Microstructure and Mechanical Properties of Inconel X-750 Welds

2011 ◽  
Vol 214 ◽  
pp. 108-112 ◽  
Author(s):  
Prachya Peasura ◽  
Bovornchok Poopat
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
Aging Temperature ◽  
Post Weld Heat Treatment ◽  
High Aging Temperature ◽  
Zone Microstructure

The Inconel X-750 indicates good hot corrosion resistance, high stability and strength at high temperatures and for this reason the alloy is used in manufacturing of gas turbine hot components. The objective of this research was study the effect of post weld heat treatment (PWHT) on fusion zone and heat affected zone microstructure and mechanical properties of Inconel X-750 weld. After welding, samples were solutionized at 1500 0C. Various aging temperature and times were studied. The results show that aging temperature and time during PWHT can greatly affect microstructure and hardness in fusion zone and heat affected zone. As high aging temperature was used, the grain size also increased and M23C6 at the grain boundary decreased. This can result in decreased of hardness. Moreover excessive aging temperature can result in increasing MC carbide intensity in parent phase (austenite). It can also be observed that M23C6 at the grain boundary decreased due to high aging temperature. This resulted in decreasing of hardness of weld metal and heat affected zone. Experimental results showed that the aging temperature 705 0C aging time of 24 hours provided smaller grain size, suitable size and intensity of MC carbide resulting in higher hardness both in weld metal and HAZ.

scholarly journals Is Superplasticity in the Future of Nanophase Materials?

1990 ◽  
Vol 196 ◽  
Author(s):  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Atomic Clusters ◽  
Diffusional Creep ◽  
Ultrafine Grain ◽  
Grain Sizes ◽  
Nanophase Materials ◽  
Boundary Sliding

ABSTRACTThe ultrafine grain sizes and high diffusivities in nanophase materials assembled from atomic clusters suggest that these materials may have a strong tendency toward superplastic mechanical behavior. Both small grain size and enhanced diffusivity can be expected to lead to increased diffusional creep rates as well as to a significantly greater propensity for grain boundary sliding. Recent mechanical properties measurements at room temperature on nanophase Cu, Pd, and TiO2, however, give no indications of superplasticity. Nonetheless, significant ductility has been clearly demonstrated in these studies of both nanophase ceramics and metals. The synthesis of cluster-assembled nanophase materials is described and the salient features of what is known of their structure and mechanical properties is reviewed. Finally, the answer to the question posed in the title is addressed.

scholarly journals Novel AM60-SiO2 Nanocomposite Produced via Ultrasound-Assisted Casting; Production and Characterization

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3976 ◽  
Author(s):  
Farzan Barati ◽  
Mojtaba Latifi ◽  
Ehsan Moayeri far ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Shear Fracture ◽  
Sio2 Nanoparticles ◽  
New Materials ◽  
Casting Method ◽  
Ultrasound Assisted ◽  
First Time ◽  
Casting Production ◽  
Composite Samples

There has been growing interest in developing new materials with higher strength-to-weight ratios. Therefore, AM60 magnesium alloy reinforced with SiO2 nanoparticles was synthesized using ultrasound-casting method for the first time, in this study. We introduced 1 and 2 wt.% of SiO2 nanoparticles into the samples. Introduction of nanoparticles led to the grain size drop in MS2 (AM60 + 2 wt.% SiO2) samples. In addition, this increased the hardness of samples from 34.8 Vickers hardness (HV) in M (AM60) to 51.5 HV in MS2, and increased the compressive strength of MS2. Improvement of the mechanical properties can be attributed to a combination of Orowan, Hall–Petch and load-bearing mechanisms. However, ductility of the composites decreased with fracture strains being 0.41, 0.39 and 0.37, respectively, for samples M, MS1 and MS2. Fracture surfaces showed shear fracture in both composite samples with microcracks and a more brittle fracture in MS2.

Effects of Nd on the Microstructure and Mechanical Property of ZA52 Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 161-164
Author(s):  
Honghui Zou ◽  
Xiao Qing Zeng ◽  
Chun Quan Zhai ◽  
Wen Jiang Ding
Keyword(s):  
Mechanical Property ◽  
Grain Boundary ◽  
Tensile Test ◽  
Total Elongation ◽  
Al Alloy ◽  
Nd Addition ◽  
A Priority ◽  
Property Changes ◽  
Microstructure And Mechanical Property

Microstructure and mechanical property changes brought by the addition of Nd element in Mg-5wt%Zn-2wt%Al alloy are investigated, results show Al element takes a priority to react with Nd element over Mg and Zn, forming binary phases Al2Nd or Al11Nd3, tensile test showed that the total elongation is improved by the addition of Nd, and the UTS is also elevated when the Nd content surpass 1wt%. With a larger Nd addition, the phase dominating grain boundary is Al11Nd3 phase.

Influence of Annealing on the Microstructure and Mechanical Properties of Electrodeposited Nanocrystalline Nickel

2011 ◽  
Vol 683 ◽  
pp. 103-112 ◽  
Author(s):  
B. Yang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Elastic Modulus ◽  
Grain Boundary ◽  
Boundary Structure ◽  
Boundary State ◽  
Microstructure And Mechanical Properties ◽  
Grain Boundary Structure ◽  
Average Grain Size ◽  
Different Grain Size

The evolution of the microstructure and mechanical properties of electrodeposited nanocrystalline Ni with different annealing procedures was studied systematically. For the annealed specimens hardness decreases with increasing average grain size but the dependence changes at different grain size ranges. The specimens annealed at a low temperature show higher hardness compared to the as-deposited nanocrystalline Ni, despite an increased measured average grain size. In association with this hardening an increase in elastic modulus and a decrease in microstrain was observed after annealing. With increasing annealing temperature both the tensile strength and the fracture strain were observed to decrease, this is companied with a transition from ductile to brittle in the fracture surfaces. These results indicated that the mechanical behaviour of nanocrystalline Ni depends not only on the average grain size but also on the grain boundary structure. A change in the grain boundary state arising from annealing may be responsible for the observed increase in hardness and elastic modulus as well as the deterioration of tensile properties.

Mechanical Properties of Porous Nanophase Materials Measured by Instrumental Indentation

1995 ◽  
Vol 400 ◽  
Author(s):  
H. Van Swygenhoven ◽  
W. Wagner ◽  
J. Löffler
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Annealing Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Condensation ◽  
Mean Grain Size ◽  
Nanophase Materials ◽  
The Mean ◽  
Instrumental Indentation

AbstractMechanical properties of nanostructured intermetallic Ni3Al synthesized by the inert-gas condensation technique are studied by means of instrumental indentation using the ICT-CSEMEX indenter. This instrument is a microindenter which continously measures load and displacement. Load-displacement curves are performed as function of grain size, consolidation- and annealing temperature. The mean grain size of the samples are studied by means of x-ray diffraction and small-angle neutron scattering.

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