Use of Computational Thermodynamics in Rapid Prototyping and Infiltrating Steel Parts

2004 ◽  
Vol 860 ◽  
Author(s):  
Brian D. Kernan ◽  
Emanuel M. Sachs ◽  
Samuel Allen
Keyword(s):  
Melting Point ◽  
Rapid Prototyping ◽  
Design Method ◽  
Tool Steels ◽  
Computational Thermodynamics ◽  
Point Depressant ◽  
Lower Melting Point ◽  
Melting Point Depressant ◽  
Manganese Steels ◽  
Conventional Tool

ABSTRACTThe direct manufacture of metal parts by rapid prototyping often involves building a porous skeleton from a metal powder. In this work, a method termed Homogeneous Steel Infiltration has been developed for infiltrating steel skeletons to make conventional tool steel alloys. The method uses a gated infiltration route that uses as the infiltrant a steel alloy with a lower melting point than the base powder. The infiltrant liquid may use carbon and/or silicon as a melting point depressant. Premature freeze-off of the steel infiltrant is avoided by operating at a temperature where some liquid is stable at chemical equilibrium. The compositions of the skeleton and infiltrant and the infiltration temperature are selected by using computational thermodynamics. Examples of successful infiltrations using D2 and A3 tool steels as target compositions are shown. The thermodynamic design method enables suitable parameters to make other tool steels, some stainless steels and manganese steels.

Wide Gap Brazing of IN 738 With Boron Free Ni-Co-Zr-Hf-Cr-Ti-Al Braze Alloy

2014 ◽  
Author(s):  
Xiao Huang
Keyword(s):  
Melting Point ◽  
Braze Alloy ◽  
Microstructure Analysis ◽  
Process Conditions ◽  
Limited Effect ◽  
Point Depressant ◽  
Powder Particles ◽  
Filler Powder ◽  
Wide Gap ◽  
Melting Point Depressant

In this study, a new boron and silicon free braze alloy, based on Ni-Co-Zr-Hf-Cr-Ti-Al, was used to repair IN 738 superalloy employing a wide gap brazing (WGB) process under two process conditions. It was found that using a combination of Hf and Zr primarily as melting point depressants the amount of each melting point depressant (MPD) could effectively be reduced while still achieving a relatively low liquidus. During WGB process, the new braze alloy was able to bond IN 738 filler powder particles to each other and to the substrate cast IN 738 and achieve defect free joint. The microstructure analysis showed the presence of Zr-containing phase(s) remained in WGB joint, however, the hardness of the Zr-containing phase(s) was similar to that of superalloy substrate. Extended brazing cycle had limited effect on reducing the Zr-containing phase(s); rather it encouraged the formation of larger eutectic γ/γ′ phases.

scholarly journals Effect of Bonding Temperature on Microstructure Evolution during TLP Bonding of a Ni3Al based Superalloy IC10

2018 ◽  
Vol 206 ◽  
pp. 03004 ◽  
Author(s):  
Xiong Yue ◽  
Fengmei Liu ◽  
Hexing Chen ◽  
Di Wan ◽  
Hongbo Qin
Keyword(s):  
Melting Point ◽  
Liquid Phase ◽  
Base Metal ◽  
Microstructure Evolution ◽  
Solidification Rate ◽  
Bonding Temperature ◽  
Transient Liquid Phase ◽  
Tlp Bonding ◽  
Point Depressant ◽  
Melting Point Depressant

Transient liquid phase (TLP) bonding of Ni3Al-based superalloy IC10 was carried out using the interlayer based on the base metal which added B and Hf as the melting point depressant elements. The effect of bonding temperature (1250 – 1270 °C) on the microstructure evolution of bonding joints were investigated. Microstructure of bonding joint composed of isothermally solidification zone (ISZ) formed γ’ phase and athermally solidified zone (ASZ) which consists of newly formed γ+γ’ reticular eutectic among with borides and carbides. Boride precipitates are not formed in diffusion affected zone (DAZ) and the boundary between ASZ and ISZ become not obvious. Isothermally solidification rate decreases as the increase of the bonding temperature.

Vacuum Brazing Porous W and Mo Using Ti-Ni-Nb Braze Alloys

2011 ◽  
Vol 410 ◽  
pp. 187-190 ◽  
Author(s):  
C.C. Lin ◽  
Chun Chen ◽  
Ren Kae Shiue ◽  
H.J. Shy ◽  
C.Steve Chang
Keyword(s):  
Melting Point ◽  
Low Temperature ◽  
Braze Alloy ◽  
Ternary Alloys ◽  
Vacuum Brazing ◽  
Novel Approach ◽  
Ni Addition ◽  
Point Depressant ◽  
Melting Point Depressant ◽  
Filler Metals

A novel approach of brazing porous W and Mo using three clad Ti-Ni-Nb foils has been performed in the experiment. Clad Ti-Ni-Nb filler foils are featured with low brazing temperature of below 1350°C. Both W and Mo are completely soluble with β-Ti and Nb, and the Ni addition into the braze alloy is served as a melting point depressant (MPD). Decreased brazing temperature and/or time are necessary in order to minimize infiltration of the molten braze into the porous W substrate. According to the experimental results, Ti-Ni-Nb ternary alloys are promising filler metals in low-temperature brazing porous W and Mo.

Synthesis and Properties of Dendrimer Liquid Crystal Based on Ester and Ether of Gallic Acid

2012 ◽  
Vol 554-556 ◽  
pp. 60-64 ◽  
Author(s):  
Min Yan Zheng ◽  
Yong Sheng Wei ◽  
Yuan Zi Gu ◽  
Shan Wang ◽  
Nai Ni Guo
Keyword(s):  
Liquid Crystal ◽  
Melting Point ◽  
Gallic Acid ◽  
Structural Unit ◽  
Optical Microscope ◽  
Heating Process ◽  
Cooling Process ◽  
H Nmr ◽  
Molecular Behavior ◽  
Lower Melting Point

With gallic acid and n-butanol as main materials, a new dendrimer micromolecular compound with the skeleton of gallic acid was synthesized by reactions of esterification and etherification of gallic acid. The structure of product was detected by elemental analysis, 1H NMR, IR and MS. The target molecule has the structure of alkyl ester and phenoether. The differential scanning calorimeter (DSC) and polarizing optical microscope (POM) measurements showed the target molecular behavior of mesophase and its streak textures belong to nematic. Its temperature range of mesophase was 78 °C during heating process and 58 °C during cooling process. The results showed that dendrimer molecule can formed with the structural unit of gallic acid and it has lower melting point and behaviors of thermotropic liquid crystal.

Research of Automobile Modeling Design Method Based on Rapid Prototyping Technology

2013 ◽  
Vol 765-767 ◽  
pp. 71-74
Author(s):  
Wen Jiang Li ◽  
Pei Cheng Shi ◽  
Ping Xiao
Keyword(s):  
Rapid Prototyping ◽  
Design Method ◽  
Low Cost ◽  
Three Dimensional ◽  
The Body ◽  
Cad Model

According to the difficulties of current China's automobile modeling design,a kind of automobile modeling design method based on rapid prototyping technology was put forward.The method has characteristics that are fast modeling,low cost and easy to modify.The main difference from the current automobile modeling design method is to make use of color pictures to establish the bodys three-dimensional CAD model directly and with the use of rapid prototyping technology to make entity model of the body.

scholarly journals Initiation of solid explosives by impact and friction: the influence of grit

1949 ◽  
Vol 198 (1054) ◽  
pp. 337-349 ◽  
Keyword(s):  
Melting Point ◽  
Hot Spots ◽  
Hot Spot ◽  
Threshold Value ◽  
Maximum Temperature ◽  
Melting Points ◽  
Solid Explosives ◽  
Lower Melting Point ◽  
Determining Factor ◽  
Spot Temperature

This paper describes an experimental study of the initiation of solid explosives, and in particular the effect of artificially introducing transient hot spots of known maximum temperature. This was done by adding small foreign particles (or grit) of known melting-point. The minimum transient hot-spot temperature for the initiation of a number of secondary and primary explosives has been determined in this way. It is shown that the melting-point of the grit is the determining factor , and all the grits which sensitize these explosives to initiation either by friction or impact have melting-points above a threshold value which lies between 400 and 550 ° C. Grit particles of lower melting-point do not sensitize the explosives. The same explosives initiated by the adiabatic compression of air required, for initiation, minimum transient temperatures of the same order as the threshold melting-point values. The results provide strong evidence that the initiation of solids as well as of liquids by friction and impact is thermal in origin and is due to the formation of localized hot spots. There is evidence that in the case of the majority of secondary explosives which melt at comparatively low temperatures, intergranular friction is not able to cause explosion and the hot spots must be formed in some other way. With the primary explosives which explode at temperatures below their melting-points, hot spots formed by intergranular friction can be important.

Microstructural Perturbations in Directionally Solidified Al-In, Al-Bi and Zn-Bi Monotectic Alloys

1981 ◽  
Vol 12 ◽  
Author(s):  
B. Toloui ◽  
A. J. Macleod ◽  
D. D. Double
Keyword(s):  
Melting Point ◽  
Temperature Gradient ◽  
Growth Velocity ◽  
Liquid Interface ◽  
Liquid Region ◽  
Directionally Solidified ◽  
Lower Melting Point ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Oscillatory Instabilities

ABSTRACTStudies have been made of the microstructures developed in directionally solidified monotectic Al-In, Al-Bi and Zn-Bi alloys, as a function of growth velocity and temperature gradient. With increasing growth velocity and decreasing gradient the microstructures show transitions from regular rod-like arrangements of the lower melting point phase, through arrays of aligned droplets to coarse irregular droplet dispersions. Intermediate stages show rods with longitudinal shape perturbations of a classic Rayleigh-type instability. The changes are discussed in terms of oscillatory instabilities at the solid-liquid interface (enhanced by increasing growth velocity and decreasing temperature gradient) coupled with ripening effects in the solid + liquid region behind the interface.

A lower-melting-point solder alloy for surface mounts

JOM ◽  
1996 ◽  
Vol 48 (5) ◽  
pp. 54-56 ◽  
Author(s):  
M. T. McCormack ◽  
Y. Degani ◽  
H. S. Chen ◽  
W. R. Gesick
Keyword(s):  
Melting Point ◽  
Solder Alloy ◽  
Lower Melting ◽  
Lower Melting Point ◽  
Surface Mounts
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