scholarly journals Study on Graphitic Steel (5th Report). Heat-treatment of Graphitic Steel of Fe-C-Si System (Part 1)

1957 ◽  
Vol 21 (11) ◽  
pp. 648-651
Author(s):  
Tomo-o Sato ◽  
Saburô Toya



Author(s):  
Yu. E. Pivinskii ◽  
P. V. Dyakin

The effect of long heat treatment (single and double firing in a tunnel kiln) of samples based on a HBCS in Al2O3‒ SiO2‒SiC-system on their indicators was studied. Samples containing 15 % SiC and 1 and 2 % Si are characterized by a significant increase (up to 9 %) an increase in porosity and a decrease in strength compared to the original samples (without SiC) after long heat treatment (120 hours in the range of 1300‒1400 oC). A significant increase in the volume of the samples is due not only to the oxidation of SiC or Si, but also to additional mullite formation. It is assumed that sequentially following the process of oxidation of SiC at a certain stage of heat treatment, the process of mullitization proceeds due to the interaction of the newly formed SiO2 in the form of cristobalite with Al2O3 bauxite. Ill. 6. Ref. 19.



Author(s):  
Yu. E. Pivinskii ◽  
P. V. Dyakin

The influence was investigated of the prolonged heat treatment on the samples properties prepared on base of the composite Al2O3‒SiO2‒SiC HCBS. The dispersion degree of the samples containing either 10 or 30 % of SiC varied within 3‒200 microns. The estimating method was proposed for the SiC oxidation degree in the composite. Depending on the samples composition the oxidation degree was within 50‒100 %. The ultimate bend strength and compressing strength SiC-containing samples attained the values of 80 and 390 MPa respectively. `````````````````````````````



Solar Energy ◽  
2015 ◽  
Vol 111 ◽  
pp. 135-150 ◽  
Author(s):  
P. Sharma ◽  
R. Sarma ◽  
L. Chandra ◽  
R. Shekhar ◽  
P.S. Ghoshdastidar


Author(s):  
R. M. Anderson

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.



Author(s):  
E. Bischoff ◽  
O. Sbaizero

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.



Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.



Author(s):  
R. Padmanabhan ◽  
W. E. Wood

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.



Author(s):  
M. A. McCoy

Transformation toughening by ZrO2 inclusions in various ceramic matrices has led to improved mechanical properties in these materials. Although the processing of these materials usually involves standard ceramic powder processing techniques, an alternate method of producing ZrO2 particles involves the devtrification of a ZrO2-containing glass. In this study the effects of glass composition (ZrO2 concentration) and heat treatment on the morphology of the crystallization products in a MgO•Al2•SiO2•ZrO2 glass was investigated.



Author(s):  
A. W. West

The influence of the filament microstructure on the critical current density values, Jc, of Nb-Ti multifilamentary superconducting composites has been well documented. However the development of these microstructures during composite processing is still under investigation.During manufacture, the multifilamentary composite is given several heat treatments interspersed in the wire-drawing schedule. Typically, these heat treatments are for 5 to 80 hours at temperatures between 523 and 573K. A short heat treatment of approximately 3 hours at 573K is usually given to the wire at final size. Originally this heat treatment was given to soften the copper matrix, but recent work has shown that it can markedly change both the Jc value and microstructure of the composite.



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