The sintering process of a high permeability Ni-Fe-Cu-Mo alloy made by powder metallurgy

1970 ◽  
Vol 5 (6) ◽  
pp. 478-486 ◽  
Author(s):  
D. L. Murrell ◽  
R. D. Enoch
Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 878 ◽  
Author(s):  
Íris Carneiro ◽  
Filomena Viana ◽  
Manuel F. Vieira ◽  
José V. Fernandes ◽  
Sónia Simões

The development of metal nanocomposites reinforced by carbon nanotubes (CNTs) remains a focus of the scientific community due to the growing need to produce lightweight advanced materials with unique mechanical properties. However, for the successful production of these nanocomposites, there is a need to consolidate knowledge about how reinforcement influences the matrix microstructure and which are the strengthening mechanisms promoting the best properties. In this context, this investigation focuses on the study of the reinforcement effect on the microstructure of an Ni-CNT nanocomposites produced by powder metallurgy. The microstructural evolution was analysed by electron backscattered diffraction (EBSD). The EBSD results revealed that the dispersion/mixing and pressing processes induce plastic deformation in the as-received powders. The dislocation structures produced in those initial steps are partially eliminated in the sintering process due to the activation of recovery and recrystallization mechanisms. However, the presence of CNTs in the matrix has a significant effect on the dislocation annihilation, thus reducing the recovery of the dislocation structures.


2015 ◽  
Vol 1087 ◽  
pp. 86-90 ◽  
Author(s):  
Murni Faridah Mahammad Rafter ◽  
Sufizar Ahmad ◽  
Rosdi Ibrahim ◽  
Rosniza Hussin ◽  
H.M. Taib

<span><span style="font-family: Times New Roman; font-size: medium;" face="Times New Roman" size="3"> </span> <p><span style="font-size: medium;" size="3"><span style="font-family: Times New Roman;" face="Times New Roman">Powder metallurgy stainless steels are retains unique benefits in preparation of porous metals due to its low cost, better wear, precise size control and corrosion resistance which are significant quality displays. In this study, the fabrication of open cellular stainless steel (SS316L) foams by using a crystalline sugar via compaction method was investigated. In this work, we show a promising method of SS316L preparation with crystalline sugar as space holder particles. Then, the foams will be given to consider the properties of SS316L foam after sintering process. Powder metallurgy process needs to go through the mixing, pressing, sintering and analysis. The selected composition of SS316L was 50 wt % and 55 wt % SS316L while the remaining percentages are foaming agent or binder. Then, sintering process was conducted in the tube furnace. The SS316L foams were characterised using X-Ray Diffraction (XRD) and Energy Diffraction X-ray (EDX). The results of this study indicate that, the XRD was detected Austenite stainless steel. Then, the detected elements in the SS316L foam were O, K, Mn, Cr, Fe, Mo and Al.</span></span></p> <span style="font-family: Times New Roman; font-size: medium;" face="Times New Roman" size="3"> </span>


2012 ◽  
Vol 520 ◽  
pp. 208-213 ◽  
Author(s):  
Shi Bo Guo ◽  
Chun Bo Cai ◽  
Yong Qiang Zhang ◽  
Yong Xiao ◽  
Xuan Hui Qu

Ti-24Nb-4Zr-7.9Sn alloy was prepared by Powder Metallurgy (PM) and Spark Plasma Sintering (SPS) using titanium hydride powder, niobium powder, zirconium powder and tin powder as raw materials. The effect of sintering process on microstructure and mechanical properties was investigated by mechanical measurement and SEM. The results showed that the best sintering process by PM was at 12500C for 2 h. The relative density, tensile strength and elongation of the alloy reached 97.2%, 705MPa and 6.2%, respectively. The microstructure was a typical Widmannstatten microstructure, which possessed β-matrix and α-precipitation. The best process by SPS was at 12500C. The relative density, tensile strength and elongation of the alloy sintered by SPS reached 99.4%, 788.5MPa and 6.4%, respectively. The grain size was about 100µm and the microstructure was uniform. The fracture morphology of the alloy was ductile rupture. Compared to PM, Ti-24Nb-4Zr-7.9Sn alloy fabricated by SPS exhibited better comprehensive properties and more uniform microstructure.


2008 ◽  
Vol 40 (1) ◽  
pp. 33-46 ◽  
Author(s):  
H. Danninger ◽  
C. Gierl

Traditionally, the common alloy elements for sintered steels have been Cu and Ni. With increasing requirements towards mechanical properties, and also as a consequence of soaring prices especially for these two metals, other alloy elements have also become more and more attractive for sintered steels, which make the steels however more tricky to process through PM. Here, the chances and risks of using in particular Cr and Mn alloy steels are discussed, considering the different alloying techniques viable in powder metallurgy, and it is shown that there are specific requirements in particular for sintering process. The critical importance of chemical reactions between the metal and the atmosphere is described, and it is shown that not only O2 and H2O but also H2 and even N2 can critically affect sintering and microstructural homogenization.


2008 ◽  
Vol 40 (1) ◽  
pp. 33-46
Author(s):  
H. Danninger ◽  
C. Gierl

Traditionally, the common alloy elements for sintered steels have been Cu and Ni. With increasing requirements towards mechanical properties, and also as a consequence of soaring prices especially for these two metals, other alloy elements have also become more and more attractive for sintered steels, which make the steels however more tricky to process through PM. Here, the chances and risks of using in particular Cr and Mn alloy steels are discussed, considering the different alloying techniques viable in powder metallurgy, and it is shown that there are specific requirements in particular for sintering process. The critical importance of chemical reactions between the metal and the atmosphere is described, and it is shown that not only O2 and H2O but also H2 and even N2 can critically affect sintering and microstructural homogenization.


2020 ◽  
Vol 30 (9) ◽  
pp. 2339-2354
Author(s):  
Meysam TOOZANDEHJANI ◽  
Farhad OSTOVAN ◽  
Khairur Rijal JAMALUDIN ◽  
Astuty AMRIN ◽  
Khamirul Amin MATORI ◽  
...  

2012 ◽  
Vol 520 ◽  
pp. 248-253
Author(s):  
Yu Wang ◽  
Cui'e Wen ◽  
Peter D. Hodgson ◽  
Yun Cang Li

In this study, a Titanium (Ti) / Strontia (SrO) composite was prepared using powder metallurgy, with the aim of obtaining advanced Ti-based composites for use as bone implant materials. Ti/SrO composites with 3 wt% SrO were fabricated using spark plasma sintering (SPS) and vacuum sintering (VS) processes. The particle morphology of ball-milled powders and the microstructure of the Ti/SrO composites were analyzed by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) equipped with energy dispersive X-spectroscope (EDX). The mechanical properties of the Ti/SrO composite were investigated using nanoindentation and hardness tests. The results showed that the Vickers hardness and nanohardness of the Ti/SrO composites fabricated by both processes were significantly higher than those of pure Ti. The Vickers hardness and nanohardness of Ti/SrO composites fabricated by the SPS process were higher than those prepared using the vacuum sintering process. The elastic modulus of Ti/SrO composites fabricated by the SPS process was higher than those samples fabricated by the vacuum sintering process which was similar to that of pure Ti.


2017 ◽  
Vol 17 (1) ◽  
pp. 47-64 ◽  
Author(s):  
Herbert Danninger ◽  
Vassilka Vassileva ◽  
Christian Gierl-Mayer

Abstract In ferrous powder metallurgy, both boron and phosphorus have been known to be sintering activators for a long time. However, the use has been widely different: while P is a standard additive to sintered iron and steels, boron has been frequently studied, but its use in practice is very limited. Both additives are also known to be potentially embrittling, though in a different way. In the present study the differences between the effects of both elements are shown: while P activates sintering up to a certain threshold, in part by stabilizing ferrite, in part by forming a transient liquid phase, boron is the classical additive enhancing persistent liquid phase, being virtually insoluble in the iron matrix. The consequence is that sintered steels can tolerate quite a proportion of phosphorus, depending on composition and sintering process; boron however is strongly embrittling in particular in combination with carbon, which requires establishing a precisely defined content that enhances sintering but is not yet embrittling. The fracture mode of embrittled materials is also different: while with Fe-P the classical intergranular fracture is observed, with boron a much more rugged fracture surface appears, indicating some failure through the eutectic interparticle network but mostly transgranular cleavage. If carbon is added, in both cases transgranular cleavage dominates even in the severely embrittled specimens, indicating that no more the grain boundaries and sintering necks are the weakest links in the systems.


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