Thermal Expandometer: A Device for Monitoring In-situ Foam Filling of Hollow Profiles Processed Through Powder Metallurgy

SiCp reinforced aluminium matrix composites (AMCs), which are widely used in the aerospace, automotive, and electronic packaging fields along with others, are usually prepared by ex situ techniques. However, interfacial contamination and poor wettability of the ex situ techniques make further improvement in their comprehensive performance difficult. In this paper, SiCp reinforced AMCs with theoretical volume fractions of 15, 20, and 30% are prepared by powder metallurgy and in situ reaction via an Al-Si-C system. Moreover, a combined method of external addition and an in situ method is used to investigate the synergistic effect of ex situ and in situ SiCp on AMCs. SiC particles can be formed by an indirect reaction: 4Al + 3C → Al4C3 and Al4C3 + 3Si → 3SiC + 4Al. This reaction is mainly through the diffusion of Si, in which Si diffuses around Al4C3 and then reacts with Al4C3 to form SiCp. The in situ SiC particles have a smooth boundary, and the particle size is approximately 1–3 μm. A core-shell structure having good bonding with an aluminium matrix was generated, which consists of an ex situ SiC core and an in situ SiC shell with a thickness of 1–5 μm. The yield strength and ultimate tensile strength of in situ SiCp reinforced AMCs can be significantly increased with a constant ductility by adding 5% ex situ SiCp for Al-28Si-7C. The graphite particle size has a significant effect on the properties of the alloy. A criterion to determine whether Al4C3 is a complete reaction is achieved, and the forming mechanism of the core-shell structure is analysed.

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Fabrication of Al/Al2O3 composites by in-situ powder metallurgy (IPM)

Powder Technology ◽

10.1016/j.powtec.2012.06.056 ◽

2012 ◽

Vol 229 ◽

pp. 276-284 ◽

Cited By ~ 35

Author(s):

S. Pournaderi ◽

S. Mahdavi ◽

F. Akhlaghi

Keyword(s):

Powder Metallurgy

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In Situ Synchrotron X-ray Study of the Mechanical Properties of Pure Mg Produced by Powder Metallurgy

Metals ◽

10.3390/met10091198 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1198

Author(s):

Li Li ◽

Leyun Wang ◽

Jie Wang ◽

Huan Zhang ◽

Qingchun Zhu ◽

...

Keyword(s):

Powder Metallurgy ◽

Tensile Deformation ◽

Line Broadening ◽

X Ray ◽

X Ray Scattering ◽

Type Dislocation ◽

Diffraction Patterns ◽

Saxs Analysis ◽

Ray Scattering

In this study, in situ synchrotron X-ray experiments with wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) detectors were performed on two pure magnesium materials produced by powder metallurgy. According to SAXS analysis, each of the two materials has a porosity of less than 0.5%. Line broadening analysis was performed on diffraction patterns collected by WAXS to analyze the dislocation evolution during material deformation. In both materials, <a>-type dislocation activities dominate the tensile deformation. The influence of grain size and texture on the different tensile behaviors of these two materials is also discussed.

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Grain Refinement of Ti-15Mo-3Al-2.7Nb-0.2Si Alloy with the Rotation of TiB Whiskers by Powder Metallurgy and Canned Hot Extrusion

Metals ◽

10.3390/met10010126 ◽

2020 ◽

Vol 10 (1) ◽

pp. 126 ◽

Cited By ~ 2

Author(s):

Jiabin Hou ◽

Lin Gao ◽

Guorong Cui ◽

Wenzhen Chen ◽

Wencong Zhang ◽

...

Keyword(s):

Powder Metallurgy ◽

Tensile Test ◽

Grain Refinement ◽

Hot Extrusion ◽

Dislocation Motion ◽

Continuous Dynamic Recrystallization ◽

Grain Sizes ◽

The Matrix ◽

Continuous Dynamic

In situ synthesized TiB whiskers (TiBw) reinforced Ti-15Mo-3Al-2.7Nb-0.2Si alloys were successfully manufactured by pre-sintering and canned hot extrusion via adding TiB2 powders. During pre-sintering, most TiB2 were reacted with Ti atoms to produce TiB. During extrusion, the continuous dynamic recrystallization (CDRX) of β grains was promoted with the rotation of TiBw, and CDRXed grains were strongly inhibited by TiBw with hindering dislocation motion. Eventually, the grain sizes of composites decreased obviously. Furthermore, the stress transmitted from the matrix to TiBw for strengthening in a tensile test, besides grain refinement. Meanwhile, the fractured TiBw and microcracks around them contributed to fracturing.

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Hot Deformation Behavior and Workability of In-Situ TiB2/7050Al Composites Fabricated by Powder Metallurgy

Materials ◽

10.3390/ma13235319 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5319

Author(s):

Haofei Zhu ◽

Jun Liu ◽

Yi Wu ◽

Qing Zhang ◽

Qiwei Shi ◽

...

Keyword(s):

Powder Metallurgy ◽

Grain Boundary Sliding ◽

Hot Workability ◽

Compression Tests ◽

Hollomon Parameter ◽

Continuous Dynamic Recrystallization ◽

Fine Grain ◽

Grain Structures ◽

Tib2 Particles

Isothermal compression tests of in-situ TiB2/7050Al composites fabricated by powder metallurgy were performed at 300–460 °C with the strain rate varying from 0.001 s−1 to 1 s−1. The Arrhenius constitutive equation and hot processing map of composites were established, presenting excellent hot workability with low activation energies and broad processing windows. Dramatic discontinuous/continuous dynamic recrystallization (DDRX/CDRX) and grain boundary sliding (GBS) take place in composites during deformation, depending on the Zener-Hollomon parameter (Z) values. It is found that initially uniform TiB2 particles and fine grain structures are beneficial to the DDRX, which is the major softening mechanism in composites at high Z values. With the Z value decreasing, dynamic recovery and CDRX around particles are enhanced, preventing the occurrence of DDRX. In addition, fine grain structures in composites are stable at elevated temperature thanks to the pinning of dense nanoparticles, which triggers the occurrence of GBS and ensures good workability at low Z values.

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Microstructure and properties of Ti-Al-Sn-Zr-Nb-Si matrix composite reinforced with in-situ TiC and Ti5Si3 prepared by powder metallurgy

Materials Research Express ◽

10.1088/2053-1591/ab3f05 ◽

2019 ◽

Vol 6 (10) ◽

pp. 1065b3 ◽

Cited By ~ 1

Author(s):

Xiaojing Xu ◽

Chong Li ◽

Vitus Mwinteribo Tabie ◽

Saifu Wang ◽

Chengbin Cai ◽

...

Keyword(s):

Powder Metallurgy ◽

Matrix Composite ◽

Microstructure And Properties ◽

In Situ Tic

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Strengthening behavior of in situ -synthesized (TiC–TiB)/Ti composites by powder metallurgy and hot extrusion

Materials & Design ◽

10.1016/j.matdes.2016.01.092 ◽

2016 ◽

Vol 95 ◽

pp. 127-132 ◽

Cited By ~ 98

Author(s):

Shufeng Li ◽

Katsuyoshi Kondoh ◽

Hisashi Imai ◽

Biao Chen ◽

Lei Jia ◽

...

Keyword(s):

Powder Metallurgy ◽

Hot Extrusion

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Wide-Gap Brazing of K417G Alloy Assisted by In Situ Precipitation of M3B2 Boride Particles

Materials ◽

10.3390/ma13143140 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3140 ◽

Cited By ~ 1

Author(s):

Zhun Cheng ◽

Xiaoqiang Li ◽

Minai Zhang ◽

Shengguan Qu ◽

Huiyun Li

Keyword(s):

Mechanical Properties ◽

Powder Metallurgy ◽

Room Temperature ◽

Distribution Characteristics ◽

Powder Metallurgy Technique ◽

Dispersion Strengthening ◽

Eutectic Transformation ◽

Wide Gap ◽

Strength And Plasticity

In this study, K417G Ni-based superalloy with a 20-mm gap was successfully bonded at 1200 °C using powder metallurgy with a powder mixture. The results indicated that the microstructure and mechanical properties of the as-bonded alloy were highly dependent on the brazing time (15–45 min), mainly due to the precipitation and distribution characteristics of M3B2 boride particles. Specifically, alloy brazed for 30 min exhibited desirable mechanical properties, such as a high tensile ultimate strength of 971 MPa and an elongation at fracture of 6.5% at room temperature, exceeding the balance value (935 MPa) of the base metal. The excellent strength and plasticity were mainly due to coherent strengthening and dispersion strengthening of the in situ spherical and equiaxed M3B2 boride particles in the γ + γ′ matrix. In addition, the disappearance of dendrites and the homogenization of the microstructure are other factors that cannot be excluded. This powder metallurgy technique, which can avoid the eutectic transformation of traditional brazing, provides a new effective method for wide-gap repair of alloy materials.

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