Differential Thermal Analysis of Complex Alloyed Brass

2019 ◽  
Vol 946 ◽  
pp. 282-286
Author(s):  
Raisa K. Mysik ◽  
Sergey V. Brusnitsyn ◽  
Andrey V. Sulitsin
Keyword(s):  
Thermal Analysis ◽  
Wear Resistance ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Volume Fraction ◽  
High Wear Resistance ◽  
Second Phase ◽  
Technological Parameters ◽  
Structure Of Alloy

Copper alloys are widely used in mechanical engineering. In the article it is shown that the requirements of consumers to properties of alloys are constantly increasing. Complex alloyed brasses have a high wear resistance and corrosion resistance. The wear resistance is a basic property of an alloy. This characteristic determines the operating life of parts working in the wear conditions. The wear resistance is supported by phase composition of alloy, uniformity of distribution of phase in the structure of alloy, their volume fraction, their morphology and their dimensions. At present time the technology of continuous casting of ingots of alloys Cu59Zn34.6Mn3.5Al2.5Fe0.5Ni0.4, Cu70Zn13Mn7Al5Fe2Si2Pb1, Cu58Zn36Mn2Pb2Si1Al1 and Cu58Zn35Mn3Si1.5Ni1.5Pb1 is developed. However, the need to use new alloys for manufacturing of critical parts requires the development of technology for their production, taking into account the composition of alloy and the features of formation of structure. Therefore, it is necessary to establish well-founded technological parameters of melting and casting of ingots of complex alloyed brass Cu62Zn31.6Mn3Al2Si0.8Ni0.4Cr0.2. For determination of temperatures of phase transformations in the structure of alloy, the differential thermal analysis was carried out. Liquidus and solidus temperatures of alloy were determined. The crystallization range of alloy was established. This brass in a solid state undergoes two phase transformations. The temperature of the first phase transformation is 750 oC. The temperature of the second phase transformation is 515 oC. The obtained experimental data make it possible to describe the proposed mechanism of phase transformations in alloy Cu62Zn31.6Mn3Al2Si0.8Ni0.4Cr0.2 during crystallization and following cooling.

Enlarging the Temperature Range for Maximum Wear Resistance of TiNi Alloy Using a NTE Phase

2007 ◽  
Vol 539-543 ◽  
pp. 3261-3266 ◽  
Author(s):  
Iulian Radu ◽  
Dong Yang Li
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Internal Stress ◽  
Frictional Heating ◽  
Negative Thermal Expansion ◽  
High Wear Resistance ◽  
Tini Alloy ◽  
Wear Loss ◽  
Second Phase ◽  
Temperature Range

The near-equiatomic TiNi alloy has been demonstrated to possess high wear resistance, which largely benefits from its pseudoelasticity (PE). However, the PE occurs only in a small temperature range, which makes the wear resistance of this alloy unstable as temperature changes, caused by environmental instability or frictional heating. Therefore, enlarging the working temperature of PE could considerably improve this alloy as a novel wear-resistant material. One possible approach is to develop a self-built temperature-dependent internal stress field by taking the advance of the difference in thermal expansion between the pseudoelastic matrix and a reinforcing phase. Such a T-dependent internal stress could adjust the martensitic transformation temperature to respond changes in environmental temperature so that the temperature range of PE could be enlarged, thus leading to a wide temperature range in which the minimum wear loss is retained. Research was conducted to investigate effects of an added second phase having a negative thermal expansion (NTE) coefficient on the wear resistance of a near-equiatomic TiNi alloy. It was demonstrated that the temperature range of this modified material in which the wear loss dropped was enlarged. In addition, the wear resistance of such a TiNi-matrix composite was on one order of magnitude higher than that of unmodified TiNi alloy.

scholarly journals Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

2003 ◽  
Vol 28 (1) ◽  
pp. 33-38 ◽  
Author(s):  
A. T. Adorno ◽  
A. V. Benedetti ◽  
R. A. G. da Silva ◽  
M. Blanco
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Transition Temperature ◽  
Phase Transformations ◽  
Decomposition Reaction ◽  
Phase Decomposition ◽  
Stability Range ◽  
X Ray ◽  
Al Content ◽  
The Stability

The influence of the Al content on the phase transformations in Cu-Al-Ag alloys was studied by classical differential thermal analysis (DTA), optical microscopy (OM) and X-ray diffractometry (XRD). The results indicated that the increase in the Al content and the presence of Ag decrease the rate of the <FONT FACE=Symbol>b</font>1 phase decomposition reaction and contribute for the raise of this transition temperature, thus decreasing the stability range of the perlitic phase resulted from the b1 decomposition reaction.

Modeling Phase Transformation Kinetics and Their Effect on Hardness and Hardness Depth in Laser Hardening of Hypoeutectoid Steel

2015 ◽  
Author(s):  
Suhash Ghosh ◽  
Chittaranjan Sahay
Keyword(s):  
Thermal Analysis ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Laser Hardening ◽  
Temperature History ◽  
Transformation Kinetics ◽  
Continuous Cooling ◽  
Phase Transformation Kinetics ◽  
Hardness Depth ◽  
Hypoeutectoid Steel

Much research has been done to model laser hardening phase transformation kinetics. In that research, assumptions are made about the austenization of the steel that does not translate into accurate hardness depth calculations. The purpose of this paper is to develop an analytical method to accurately model laser hardening phase transformation kinetics of hypoeutectoid steel, accounting for non-homogeneous austenization. The modeling is split into two sections. The first models the transient thermal analysis to obtain temperature time-histories for each point in the workpiece. The second models non-homogeneous austenization and utilizes continuous cooling curves to predict microstructure and hardness. Non-homogeneous austenization plays a significant role in the hardness and hardness depth in the steel. A finite element based three-dimensional thermal analysis in ANSYS is performed to obtain the temperature history on three steel workpieces for laser hardening process with no melting; AISI 1030, 1040 and 1045 steels. This is followed by the determination of microstructural changes due to ferrite and pearlite transformation to austenite during heating and the subsequent austenite to martensite and other diffusional transformations during cooling. Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation is used to track the phase transformations during heating, including the effects of non-homogenous austenitization. The solid state nodal phase transformations during cooling are monitored on the material’s digitized Continuous Cooling Transformation (CCT) curve through a user defined input file in ANSYS for all cooling rates within the Heat Affected Zone (HAZ). Material non-linearity is included in the model by including temperature dependent thermal properties for the material. The model predictions for hardness underneath the laser and the HAZ match well with the experimental results published in literature.

Study of Phase Transformation in Alloys of the Al-Fe System

2012 ◽  
Vol 326-328 ◽  
pp. 573-577 ◽  
Author(s):  
Magdalena Jabłońska ◽  
Marta Mikuśkiewicz ◽  
Anna Śmiglewicz ◽  
E. Bernstock-Kopaczyńska
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Order Type ◽  
Point Of View ◽  
Gravity Casting ◽  
Mechanical And Physical Properties ◽  
Temperatures Of Phase Transformations ◽  
Alloys Of The Al

In this paper, phase transformation in alloys of the Al-Fe and Al-Fe-Cr systems was investigated. The alloys were prepared by melting and gravity casting. The studies of phase transformation were carried out on samples after casting and annealing, using the differential thermal analysis (DTA) and dilatometric method. The knowledge on the phase transformations in these alloys including the information about order-disorder transition is very important from the point of view of obtained mechanical and physical properties of alloys of the Al-Fe system. These results are an important contribution in development of knowledge on iron aluminides. In the article, temperatures of phase transformations connected with a change in order type and transition into disordered solid solution were defined. Conformity of the recorded DTA results and dilatometric analysis was achieved.

An Automatic Selection of Segment Width for the Single Sensor Differential Thermal Analysis (SS-DTA) Based on Piecewise Linear Approximation Technique

2015 ◽  
Vol 658 ◽  
pp. 96-100 ◽  
Author(s):  
Wutipong Nieampradit ◽  
Sarawan Wongsa ◽  
Isaratat Phung-On
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Linear Approximation ◽  
Piecewise Linear ◽  
Research Work ◽  
Piecewise Linear Approximation ◽  
Approximation Technique ◽  
Analytical Formulae ◽  
Single Sensor

Single Sensor Differential Thermal Analysis (SS-DTA) is a novel non-destructive testing technique for studying and detecting the phase transformations and structural changes in materials. It uses only one temperature sensor to measure the temperature in a particular point of interest in the material during actual and simulated thermal processing of the material. SS-DTA compares the temperature recorded in a tested specimen against a reference thermal profile which can be generated either by analytical formulae or piecewise linear approximation. The main advantage of piecewise linear approximation over the analytical formulae is that it does not need the knowledge of tested material and processing conditions to optimally estimate the parameters of reference thermal history. On the other hand, in order to apply the piecewise linear approximation technique we must specify the segment width which is normally fixed at a nominal value of 1.5 seconds. We have recently found that this nominal value might not be an optimal choice for the segment width as it does not guarantee to give the best detectability of phase transformation. Therefore, in this research work we proposed a technique to automatically select an appropriate value of the segment width. The performance of proposed method has been evaluated by investigating the phase transformations of welded stainless steel SUS 321and SUS 304. It was found that the appropriate segment width could be ranging from 1.25-1.75 seconds and by using this selection technique, we could detect the differential temperature more accurately than when using the nominal value.

Effect of carbides on the wear resistance of white cast iron alloyed with 12.7 wt.-% Cr and nickel

2020 ◽  
Vol 62 (8) ◽  
pp. 788-792
Author(s):  
Tanju Teker ◽  
S. Osman Yilmaz ◽  
Tekirdağ Teker
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Volume Fraction ◽  
High Wear Resistance ◽  
Homogeneous Distribution ◽  
Nickel Concentration ◽  
Carbide Size ◽  
Wear Tests

Abstract White cast iron with about 12.7 wt.-% chromium was alloyed with Ni, W and Mo for heat treatment applications. Heat treatments were performed at a range of 850-1050 °C for 1 h in order to distribute M7C3 carbides homogeneously in an environment of high wear resistance. The contents of the C, Cr, Ni, Mo, Mn and Si elements selected for the alloys were similar, though a 6 wt.-% nickel concentration was chosen. Microstructural changes in the specimens were examined by scanning electron microscopy (SEM) and optical microscopy (OM). Macro-hardness, average carbide size and volume fraction were analyzed. Wear tests were carried out under different loads of 10, 20 and 30 N. It was seen that heat treatment changed the carbide size and homogeneous distribution of the carbides. Moreover, the addition of nickel to HCrWCI increased fracture toughness and reduced the wear rate.

Phase Transformations in the Quenched Alloy Based on Orthorhombic Titanium Aluminide during Heating

2021 ◽  
Vol 316 ◽  
pp. 473-478
Author(s):  
A.G. Illarionov ◽  
S.V. Grib ◽  
A.A. Popov
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Transformations ◽  
Titanium Aluminide ◽  
Phase State ◽  
Heating Temperature ◽  
Continuous Heating ◽  
Temperature Ranges ◽  
Orthorhombic Titanium ◽  
Heating Up

Phase transformations in the alloy based on the orthorhombic titanium aluminide (Ti-24,3Al-24,8Nb-1,4V-1,0Zr-0,6Mo-0,3Si – at. %) were studied by differential thermal analysis. The alloy was quenched from the different phase regions (β+O, β+O+α2+(Vω), β+α2, β) and was subjected to continuous heating up to . It was found that the heating temperature of the O-alloy, which determines its phase state during quenching, affects the temperature ranges, intensity, and stages of the phase transformations during subsequent heating.

scholarly journals Thermal Annealing and Phase Transformation of Serpentine-Like Garnierite

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Micro Raman Spectroscopy

This study is focused on the vibrational and microstructural aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite were annealed in static air between room temperature and 1000 °C. The kinetic of the transformation was investigated by means of thermogravimetric and differential thermal analysis, and the final product was extensively characterized via micro-Raman spectroscopy and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

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