Water as a melting point depressant for acrylic polymers

1982 ◽  
Vol 7 (1) ◽  
Author(s):  
BruceG. Frushour
Keyword(s):  
Melting Point ◽  
Acrylic Polymers ◽  
Point Depressant ◽  
Melting Point Depressant

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.

Liquation Cracking in Heat Affected Zone in Ni Superalloy Welds

2007 ◽  
Vol 546-549 ◽  
pp. 1163-1170 ◽  
Author(s):  
Mahesh C. Chaturvedi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Heat Affected Zone ◽  
Turbine Engines ◽  
High Temperature Strength ◽  
Intergranular Cracking ◽  
Point Depressant ◽  
Haz Cracking ◽  
Melting Point Depressant ◽  
Industrial Gas Turbine

Precipitation hardened nickel-based superalloys are widely used in aero and industrial gas turbine engines due to their excellent high temperature strength and remarkable hot corrosion resistance. A drawback of many of these alloys is that they are very difficult to weld due to their high susceptibility to heat affected zone (HAZ) cracking, both during welding and post weld heat treatments (PWHT). Weld cracking in many of these alloys has been attributed mostly to constitutional liquatioin of grain boundary NbC precipitates. however, HAZ cracking has been observed in carbon-free superalloys as well, Therefore, research was initiated to examine grain boundary liquation and cracking in HAZs in a variety of Ni-based superalloys. It was found that intergranular cracking of grain boundaries involved liquation of several other phases, in addition to NbC, that were present in pre-weld microstructure of the alloy. These even included the primary strengthening phase,γ’, in a very widely used superalloy, Inconel 738. In addition, segregation of melting point depressant element B was also observed at gain boundaries in other superalloys, which also caused grain boundaries in HAZ to liquate and resulting in their cracking. An overview of microstructural aspects of different liquation phenomena involved and characteristics of the liquid film contributing to the HAZ microfissuring of nickel superalloys will be discussed in this presentation

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

The observation of nano-voids in Au thin films

1987 ◽  
Vol 45 ◽  
pp. 366-367
Author(s):  
William Krakow
Keyword(s):  
Thin Films ◽  
Melting Point ◽  
Present Author ◽  
Stacking Faults ◽  
Damage Threshold ◽  
Ionic Species ◽  
Rare Gases ◽  
Chain Defects ◽  
Vacancy Chains ◽  
Au Thin Films

It has long been known that defects such as stacking faults and voids can be quenched from various alloyed metals heated to near their melting point. Today it is common practice to irradiate samples with various ionic species of rare gases which also form voids containing solidified phases of the same atomic species, e.g. ref. 3. Equivalently, electron irradiation has been used to produce damage events, e.g. ref. 4. Generally all of the above mentioned studies have relied on diffraction contrast to observe the defects produced down to a dimension of perhaps 10 to 20Å. Also all these studies have used ions or electrons which exceeded the damage threshold for knockon events. In the case of higher resolution studies the present author has identified vacancy and interstitial type chain defects in ion irradiated Si and was able to identify both di-interstitial and di-vacancy chains running through the foil.

Benzene confined in MCM-41 below its melting point : A proton NMR study

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-99-Pr7-102 ◽  
Author(s):  
G. Dosseh ◽  
D. Morineau ◽  
C. Alba-Simionesco
Keyword(s):  
Melting Point ◽  
Proton Nmr ◽  
Nmr Study ◽  
Mcm 41
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