Al-Cr Diffusion Coatings Processed on a Cast and a Heat-Treated Ni-Base Alloy

2021 ◽  
Vol 10 (1) ◽  
pp. 20210059
Author(s):  
Alana S. Dalpasquale ◽  
Ana Sofia C. M. D’Oliveira
1998 ◽  
Vol 4 (S2) ◽  
pp. 118-119
Author(s):  
M. Thuvander ◽  
K. Stiller

Segregation of boron, carbon and nitrogen to grain boundaries in a nickel based model alloy has been investigated using atom probe field ion microscopy (APFIM). The material corresponds to a commercial alloy (Inconel 600), but contains lower levels of alloy additives and impurities. The major composition was Ni-16Cr-10Fe (wt.%). The alloy was solution annealed at 950°C for 10 min, which resulted in a grain size of 20 μ. Subsequently heat treatments for 1 h at temperatures of 550°C, 600°C and 700°C were applied. TEM investigation showed that the heat treatment at 700°C resulted in precipitation of intergranular chromium-rich carbides. The other temperatures were obviously too low and the aging times too short to cause precipitation, since carbides were not observed in the materials heat treated at 550°C and 600°C.As the grain size was about 100 times larger than the accessible depth of APFIM analysis (≃200 nm), much care had to be taken in preparing samples containing a grain boundary close to the tip apex.


Author(s):  
Kun Liu ◽  
Emad Elgallad ◽  
Chen Li ◽  
X.-Grant. Chen

Abstract The present work investigated the influence of Zr and Sc on the evolution of α-Al(FeMn)Si dispersoids (“α-dispersoids") in Al–Mg–Si alloys. Both the individual addition of Zr and the combined additions of Sc and Zr increased the size but decreased the number density of the α-dispersoids, indicating the reduction in the formation of α-dispersoids. However, the reduction levels were the most significant when heat-treated at 350 °C in the alloy with both Sc and Zr and at 400 °C in the alloy with only Zr, which were likely related to the different interactions between intermediate B’ precipitates and α-dispersoids with the addition of Zr and Sc. Although the α-dispersoids were suppressed in the Zr/Sc-containing alloys, their microhardness was generally higher than the base alloy, which can be attributed to the strengthening contribution induced by Zr and Sc either from their solid solution hardening or the precipitation hardening of Al3Zr/Al3(Sc, Zr) dispersoids.


2020 ◽  
Vol 34 (25) ◽  
pp. 2050261
Author(s):  
Yingwu Wang ◽  
Xiaoqing Zuo ◽  
Songjiang Ran ◽  
Yushun Ye ◽  
Jihua Tian

The effects of semi-solid extrusion temperature change, extrusion pressure, SiC content and T5 heat treatment on the microstructure, mechanical properties, and wear resistance of SiC particle strengthened high aluminum zinc-base alloy [Formula: see text] composites were studied. The results show that semi-solid extrusion broke the dendrites of [Formula: see text] composites, refined their grain structure, and improved particle aggregation. The density, hardness, yield strength, tensile strength and elongation of [Formula: see text] composites first increased and then decreased when the extrusion temperature and SiC content increased, and also increased when the extrusion pressure rose. The optimal extrusion temperature, pressure and SiC content are 475[Formula: see text], 15 MPa and 10 wt.%, respectively. T5 heat treatment further refined the crystalline grains and promoted [Formula: see text] and [Formula: see text] to precipitate as strengthening phases, which improve the mechanical properties and wear resistance of [Formula: see text] composites. Consequently, the hardness, yield strength, tensile strength and elongation of the heat-treated composites improved by 18.99%, 9.66%, 4.93% and 9.76%, respectively. The wear loss of the heat-treated composites reduced by 31.65% under a load of 1600 N and a rotational speed of 200 r/min compared with the as-cast composites.


2021 ◽  
Author(s):  
Sugrib Kumar Shaha

High temperature tensile, compression and low cycle fatigue tests were performed to assess the influence of micro-additions of Ti, V and Zr on the Al-7Si-1Cu-0.5Mg (wt.%) alloy in the as-cast and heat treated conditions. A combination of electron microscopy and high temperature X-ray diffraction was used to identify phases and temperature ranges of their thermal stability. The microstructure of the as-cast Al-7Si-1Cu-0.5Mg (wt.%) base and modified alloys consisted of α-Al, eutectic Si, and Cu-, Mg- and Fe-based phases Al2.1Cu, Al8.5Si2.4Cu, Al7.2Si8.3Cu2Mg6.9 and Al14Si7.1FeMg3.3. In addition, the micro-sized Ti/V/Zr-rich phases Al6.8Si1.4Ti, Al21.4Si4.1Ti3.5VZr3.9, Al6.7Si1.2TiZr1.8, Al2.8Si3.8V1.6Zr and Al5.1Si35.4Ti1.6Zr5.7Fe were identified in the modified alloys. During solution treatment, Cu- and Mg- based phases were completely dissolved, while the eutectic silicon, Fe- and Ti-V-Zr-rich intermetallics partially dissolved. The TEM analysis confirmed the presence of nano-sized precipitates of (AlSi)3(TiVZr) with D023 tetragonal crystal structure. The tensile tests of the alloy in the as-cast state showed that with increasing testing temperature from 25°C to 400°C the yield strength and tensile strength of the studied alloy decreased from 161 MPa to 84 MPa and from 261 MPa to 102 MPa, respectively. Accordingly, the T6 heat treated alloy modified with additions of a higher content of Ti-V-Zr achieved the highest tensile strength of 343 MPa over the base alloy and alloys modified with additions of Ti, Ti-Zr and lower contents of Ti-V-Zr. The fatigue life of the studied alloy in the T6 condition was substantially longer than those of the reference alloys A356 and the same Al-7Si-1Cu-0.5Mg base alloy with lower additions of V, Zr and Ti in the T6 condition. The fractography revealed tensile crack propagation through the eutectic Si and primary phases, exhibiting intergranular fracture along with some cleavage-like features of the plate-shaped Ti-V-Zr-rich intermetallics with a presence of fatigue striations on the latter, indicating their ductile nature. It is believed that the intermetallic precipitates containing Zr, Ti and V improve the fatigue life of the studied alloy in the T6 condition.


Alloy Digest ◽  
1956 ◽  
Vol 5 (6) ◽  

Abstract DOWMETAL AZ91C is a heat treatable magnesium base alloy suitable for sand and permanent mold castings. It combines good tensile strength and yield strength with good elongation and is used in both the solution heat treated condition (T4) and in the solution heat treated plus artificially aged condition (T6). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as heat treating, machining, and joining. Filing Code: Mg-25. Producer or source: The Dow Chemical Company, Bay City Division.


Alloy Digest ◽  
1980 ◽  
Vol 29 (6) ◽  

Abstract CRUCIBLE C-120AV is an alpha-beta type titanium-base alloy with 120,000 psi minimum yield strength in the annealed condition. It has good forming characteristics, is weldable with proper shielding and can be heat treated to high strength levels by solution treating and aging. Its many applications include components for gas-turbine compressors, air-frame forgings, pressure vessels and special ordnance equipment. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear and bend strength as well as fracture toughness, creep, and fatigue. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ti-77. Producer or source: Crucible Specialty Metals Division, Colt Industries.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1076 ◽  
Author(s):  
Marco A.L. Hernandez-Rodriguez ◽  
Rafael D. Mercado-Solis ◽  
Gerardo Presbítero ◽  
Diego E. Lozano ◽  
Gabriela M. Martinez-Cazares ◽  
...  

Cobalt-based alloys are widely used in the manufacture of joint prostheses. In this study, the effect of boron additions and heat treatment on the ASTM F75 was evaluated by rotating bending fatigue. The boron ranged from 0.06–1 wt %. The alloys were tested in as-cast and heat-treated conditions. In the as-cast condition, the infinite life was observed at 380 MPa, improving to 433–615 MPa according to the amount of boron added. In the heat treatment condition, the fatigue resistance was improved only in the base alloy. The addition of 0.06 wt % boron and heat treatment led to the same resistance as in the as-cast condition. Adding large amounts of boron combined with heat treatment diminished the fatigue limit. The fracture analysis revealed primarily brittle behaviour with some ductile features even on the same sample; only the heat-treated alloy with 0.06 wt % boron was clearly ductile. This alloy also exhibited notably better toughness to crack propagation.


Author(s):  
Karl Dawson ◽  
Gordon J. Tatlock

The duration of post weld heat treatments (PWHT) applied to thick section multi-pass dissimilar metal welds (DMW), involving ferritic creep resistant steels of differing chromium content, are shown to have a considerable impact on the performance of the welded joint. Welding consumables of alloy types P22 and P24 have been used to form joints with P91 base alloy which were subsequently post weld heat treated for varying durations. High resolution transmission electron microscopy (TEM) has been exploited in the characterisation of precipitation in the weld material and the heat affected zone. It has been shown that uphill diffusion of carbon from the low to the higher alloy material during PWHT and creep test conditions occurs in all specimens. Selected area diffraction (SAD) and convergent beam electron diffraction (CBED) studies of carbon extraction replicas reveal extensive dissolution of M23C6 and M7C3 carbides in the decarburised zone of the weld alloy subsequent to post weld heat treatments. However, welds completed using Nb and V containing consumables retain a fine distribution of MX precipitation in the carbon depleted regions after PWHT. The retention of these microstructure stabilising carbonitrides facilitates the preservation of an ultra fine sub-grain microstructure, thus avoiding recrytallisation which is invariably observed in post weld heat treated P22:P91 DMWs. Cell size comparisons of the sub-grain microstructures have been investigated utilising channelling contrast back scattered scanning electron images of as welded and post weld heat treated material.


2015 ◽  
Vol 67 (4) ◽  
pp. 292-300 ◽  
Author(s):  
TS Kiran ◽  
M Prasannakumar ◽  
S Basavarajappa ◽  
BM Viswanatha

Purpose – The purpose of the paper is to study the dry sliding wear behavior of as-cast and heat-treated zinc-aluminum (ZA-27) alloy, reinforced with silicon carbide and graphite particles. Design/methodology/approach – The alloy and composite samples were prepared with stir casting technique. Heat treatment was carried out for samples at a temperature of 370°C followed by quenching in water at room temperature. Subsequently, the heat-treated samples were aged at 180°C and quenched in water at room temperature. The wear tests were carried using pin-on-disc apparatus at room temperature at different applied loads, sliding speed and sliding distance. Findings – The wear volume loss of as-cast samples was more compared with heat treated samples. Composites exhibited improved wear resistance than base alloy. Originality/value – Hybrid metal matrix composites with heat treatment has exhibited superior wear behavior in dry sliding conditions.


2015 ◽  
Vol 1760 ◽  
Author(s):  
Daisuke Edatsugi ◽  
Yasuyuki Kaneno ◽  
Hiroshi Numakura ◽  
Takayuki Takasugi

ABSTRACTThe effect of W addition on microstructure and mechanical properties of Ni3Al (L12) and Ni3V (D022) two-phase intermetallic alloys has been investigated. W was added to the base alloy composition, Ni75Al10V12Nb3 (at. %) in place of either Ni, Al or V. The W-added alloy ingots were heat-treated in vacuum at 1575 K for 5 h. The majority of W-added alloys showed a dual two-phase microstructures while the alloy in which 3 at. % W substituted for Ni exhibited the dual two-phase microstructure containing W solid solution dispersions. Vickers hardness was significantly enhanced by W addition, which is primarily due to solid-solution strengthening.


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