scholarly journals The Microstructure Evolution and Mechanical Properties of TiBw/TA15 Composite with Network Structure Prepared by Rapid Current Assisted Sintering

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 540 ◽  
Author(s):  
Dongjun Wang ◽  
Hao Li ◽  
Xiaosong Wang ◽  
Wei Zheng ◽  
Zhangqian Lin ◽  
...  
Keyword(s):  
Yield Strength ◽  
Microstructure Evolution ◽  
Average Diameter ◽  
Strengthening Mechanism ◽  
Strengthening Effect ◽  
Alloy Matrix ◽  
Microstructure Modification ◽  
Ta15 Titanium Alloy ◽  
Average Aspect Ratio ◽  
Rapid Current

TiBw/TA15 (TA15 alloy reinforced by TiB whiskers) composites with network microstructures were successfully prepared by current-assisted sintering at 1100 °C for 10 min. The influence of the sintering parameters on the microstructures of obtained composites was investigated. The sintering temperature was the main factor affecting the average aspect ratio of TiBw, and the average diameter of TiBw could be controlled for various sintering conditions. Yield strength, ultimate compressive strength, and plastic strain at ambient temperature are 1172.5 MPa, 1818.4 MPa, and 22.4% for the TiBw/TA15 composites, respectively. Moreover, yield strength of the composites at 600 °C is 616.3 MPa, which is 26.1% higher than that of the TA15 titanium alloy. The effect of the TiBw on the microstructure evolution for the alloy matrix was discussed in detail. The strengthening mechanism of the TiBw/TA15 composites with network microstructure was attributed to the microstructure modification induced by TiBw, load bearing effect, and dislocation strengthening effect of the TiBw.

Effects of Nb on the High Temperature Mechanical Properties of TiNiAl Alloys

2007 ◽  
Vol 546-549 ◽  
pp. 1477-1480 ◽  
Author(s):  
Gao Song Qiu ◽  
Xin Qing Zhao ◽  
Ling Jie Meng ◽  
Hui Bin Xu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Yield Stress ◽  
Microstructure Evolution ◽  
High Yield ◽  
Strengthening Effect ◽  
High Temperature Mechanical Properties ◽  
Solution Strengthening ◽  
Nb Addition

A series of NiTiAl based alloys with different amount of Nb addition were prepared and the effects of Nb on both the mechanical properties and microstructure evolution were investigated. The addition of Nb can remarkably enhance the high temperature yield strength of these alloys. The highest yield strength of the alloys with 10 at% Nb reaches 1237MPa at 873K and 875MPa at 973K, respectively. The Ti2Ni(Al,Nb) precipitates and the solution strengthening effect might be responsible for the high yield stress achieved at high temperature.

scholarly journals Probability-Dependent Precipitation Strengthening Effect of Anisotropic Precipitate in Al-Mg-Si Alloy Produced by T6 Heat Treatment

2021 ◽  
Vol 59 (8) ◽  
pp. 515-523
Author(s):  
Seunggyu Choi ◽  
Gwanghun Kim ◽  
Jin Pyeong Kim ◽  
Se Hoon Kim ◽  
Seung Bae Son ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Metastable Phase ◽  
Precipitation Strengthening ◽  
Precipitate Size ◽  
Strengthening Effect ◽  
Alloy Matrix ◽  
Gravity Casting ◽  
T6 Heat Treatment ◽  
Critical Resolved Shear Stress

This study proposed a constitutive equation to predict the change in yield strength according to the behavior of β″ metastable precipitates, which have a profound effect on strength among materials precipitated during the T6 heat treatment of Al-Mg-Si alloy. The β″ precipitate is a metastable phase before it becomes a β (Mg2Si) precipitate, and is distributed in the form of nano-scale rods in the aluminum alloy matrix. Existing precipitation strengthening models assume the shape of the precipitate to be spherical, and in that case the equation that depends on the Orowan mechanism with the average precipitate size and distribution should dominate. However, precipitates are formed in various shapes and sizes by anisotropic growth. In particular, rod-shaped precipitates are not suitable for the existing precipitation strengthening model. In this study, an Al-Mg-Si alloy was fabricated by gravity casting followed by T6 heat treatment. The new precipitation strengthening effect equation proposes that the β″ precipitate affects yield strength during plastic deformation of the Al-Mg-Si alloy. The proposed precipitation strengthening effect equation probabilistically considers the Critical Resolved Shear Stress (CRSS), which varies depending on the angle between the dislocation and the precipitate, when the dislocation passes through a rod-shaped precipitate.

scholarly journals ODS EUROFER Steel Strengthened by Y-(Ce, Hf, La, Sc, and Zr) Complex Oxides

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1148 ◽  
Author(s):  
Roman Husák ◽  
Hynek Hadraba ◽  
Zdeněk Chlup ◽  
Milan Heczko ◽  
Tomáš Kruml ◽  
...  
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Complex Oxides ◽  
Oxide Dispersion Strengthened ◽  
Interparticle Spacing ◽  
Oxide Dispersion ◽  
Strengthening Effect ◽  
Dispersion Strengthening ◽  
Doping Element ◽  
Average Grain Size

Oxide dispersion-strengthened (ODS) materials contain homogeneous dispersions of temperature-stable nano-oxides serving as obstacles for dislocations and further pinning of grain boundaries. The strategy for dispersion strengthening based on complex oxides (Y-Hf, -Zr, -Ce, -La) was developed in order to refine oxide dispersion to enhance the dispersion strengthening effect. In this work, the strengthening of EUROFER steel by complex oxides based on Y and elements of the IIIB group (lanthanum, scandium) and IVB group (cerium, hafnium, zirconium) was explored. Interparticle spacing as a dispersoid characteristic appeared to be an important factor in controlling the dispersion strengthening contribution to the yield strength of ODS EUROFER steels. The dispersoid size and average grain size of ODS EUROFER steel were altered in the ranges of 5–13 nm and 0.6–1.7 µm, respectively. Using this strategy, the yield strength of the prepared alloys varied between 550 MPa and 950 MPa depending on the doping element.

scholarly journals Reinforcement of Recycled Aggregate by Microbial-Induced Mineralization and Deposition of Calcium Carbonate—Influencing Factors, Mechanism and Effect of Reinforcement

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 887
Author(s):  
Chunhua Feng ◽  
Buwen Cui ◽  
Haidong Ge ◽  
Yihong Huang ◽  
Wenyan Zhang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Global Economy ◽  
Low Cost ◽  
High Water ◽  
Strengthening Mechanism ◽  
Recycled Aggregate ◽  
Strengthening Effect ◽  
Calcium Carbonate Precipitation ◽  
Environmental Friendliness ◽  
Advantages And Disadvantages

Recycled aggregate is aggregate prepared from construction waste. With the development of a global economy and people’s attention to sustainable development, recycled aggregate has shown advantages in replacing natural aggregate in the production of concrete due to its environmental friendliness, low energy consumption, and low cost. Recycled aggregate exhibits high water absorption and a multi-interface transition zone, which limits its application scope. Researchers have used various methods to improve the properties of recycled aggregate, such as microbially induced calcium carbonate precipitation (MICP) technology. In this paper, the results of recent studies on the reinforcement of recycled aggregate by MICP technology are synthesized, and the factors affecting the strengthening effect of recycled aggregate are reviewed. Moreover, the strengthening mechanism, advantages and disadvantages of MICP technology are summarized. After the modified treatment, the aggregate performance is significantly improved. Regardless of whether the aggregate was used in mortar or concrete, the mechanical properties of the specimens were clearly improved. However, there are some issues regarding the application of MICP technology, such as the use of an expensive culture medium, a long modification cycle, and untargeted mineralization deposition. These difficulties need to be overcome in the future for the industrialization of regenerated aggregate materials via MICP technology.

Preparation and Characterization of Carbon Fibre Reinforced Aluminium Matrix Composite

2011 ◽  
Vol 686 ◽  
pp. 758-764 ◽  
Author(s):  
Xiao Ming Sui ◽  
Xi Liang Xu ◽  
Xiao Meng Zheng ◽  
Guang Zhi Xu ◽  
Qiang Wang
Keyword(s):  
Carbon Fiber ◽  
Aluminum Matrix ◽  
Strengthening Mechanism ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Alloy Matrix ◽  
Aluminium Matrix Composite ◽  
Carbon Fiber Reinforced ◽  
Long Carbon Fiber

Driven by the increasing requirements from aircraft producers, aluminium alloy matrix composites with carbon fiber reinforcement have been largely used in the modern industry. The method of traditional preparation of carbon fiber reinforced aluminum matrix composites is not only high cost and complex to produce but also difficult to apply in the civilian. The present paper focuses on exploratory study on the preparation of carbon-fiber- reinforced aluminum composites, the intensifying material is continuous long carbon fiber. In order to avoid any interfacial reactions in the carbon fiber reinforced composites, the carbon fibers were coated with copper. We made The tensile samples were made by using the mould, the tensile properties determined, the strengthening mechanism studied, and the carbon fiber in the matrix observed with the microscope.

Effect of Tempering Time on Microstructure and Mechanical Properties of SA738 Gr.B Steel

2021 ◽  
Vol 1016 ◽  
pp. 1739-1746
Author(s):  
Yan Mei Li ◽  
Shu Zhan Zhang ◽  
Zai Wei Jiang ◽  
Sheng Yu ◽  
Qi Bin Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Yield Strength ◽  
Microstructure Evolution ◽  
Impact Energy ◽  
Nuclear Power ◽  
Microstructure And Mechanical Properties ◽  
The Impact ◽  
Tempering Time

The effect of tempering time on the microstructure and mechanical properties of SA738 Gr.B nuclear power steel was studied using SEM, TEM and thermodynamic software, and its precipitation and microstructure evolution during tempering were clarified. The results showed that SA738 Gr.B nuclear power steel has better comprehensive mechanical properties after tempering at 650 °C for 1h. With the extension of the tempering time, M3C transformed into M23C6 with increasing size, which affected the yield strength and impact energy. When the tempering time is 8h ~ 10h, due to the transformation of M3C to M23C6, the composition of matrix around the carbide changed, causing the temperature of Ac1 dropped, forming twin-martensite which deteriorated the impact toughness of the steel.

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