EFFECT OF VACUUM INDUCTION MELTING TECHNOLOGY ON MECHANICAL PROPERTIES OF Nb-16Si-22Ti-2Al-2Hf-17Cr ALLOY

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2940-2945 ◽  
Author(s):  
XIAOJIAN LI ◽  
HU ZHANG ◽  
JIANGBO SHA

This paper dealt with the effect of different induction melting technologies on mechanical properties of Nb -16 Si -22 Ti -2 Al -2 Hf -17 Cr alloy. The cast ingots were fabricated first by arc-melting, and then remolten in the vacuum induction furnace. The results showed that the ingot with refining process of 1800°C/15min and 0.1 at% C addition had finer microstructure and higher room-temperature fracture toughness. In addition, the compressive strength of the ingot with refining technology of 1700°C/10min was 315MPa at 1250°C. However, the arc melting ingot had the lowest fracture toughness and high-temperature compressive strength.

2017 ◽  
Vol 898 ◽  
pp. 454-460
Author(s):  
Mei Ling Wu ◽  
Feng Wei Guo ◽  
Ming Li ◽  
Yong Wang Kang ◽  
Ya Fang Han

The Nb-Si system ultrahigh temperature alloys were prepared by vacuum non-consumable arc melting. The influence of micro-alloying elements of B and Ce on the hardness, room-temperature fracture toughness and compressive strength at 1250°C of the Nb-22Ti-3Si alloys was investigated and estimated systematically. The results showed that the hardness of the Nb-22Ti-3Si alloy increased obviously with trace B addition, but decreased slightly with trace Ce addition. The room-temperature fracture toughness of the Nb-22Ti-3Si alloy was degraded by the Ce addition but improved by the trace addition of B. The trace addition of B improved the compressive strength of the alloy at 1250°C. In contrast, the trace Ce addition degraded the compressive strength at 1250°C. The relationship between the microstructure and the mechanical properties was discussed.


2021 ◽  
Vol 2103 (1) ◽  
pp. 012075
Author(s):  
AA Dmitrievskiy ◽  
DG Zhigacheva ◽  
VM Vasyukov ◽  
PN Ovchinnikov

Abstract In this work, the phase composition (relative fractions of monoclinic m-ZrO2, tetragonal t-ZrO2, and cubic c-ZrO2 phases) and mechanical properties (hardness, fracture toughness, compressive strength) of alumina toughened zirconia (ATZ) ceramics, with an addition of silica were investigated. Calcium oxide was used as a stabilizer for the zirconia tetragonal phase. It was shown that CaO-ATZ+SiO2 ceramics demonstrate increased resistance to low-temperature degradation. The plasticity signs at room temperature were found due to the SiO2 addition to CaO-ATZ ceramics. A yield plateau appears in the uniaxial compression diagram at 5 mol. % SiO2 concentration. It is hypothesized that discovered plasticity is due to the increased t→m transformability.


2021 ◽  
Vol 1035 ◽  
pp. 89-95
Author(s):  
Chao Tan ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Xiao Zhao Ma ◽  
Zi An Yang

A new type of Ti-Al-Sn-Zr-Mo-Si series high temperature titanium alloy was prepared by a water-cooled copper crucible vacuum induction melting method, and its phase transition point was determined by differential thermal analysis to be Tβ = 1017 °C. The influences of solution temperature on the microstructures and mechanical properties of the as-forged high temperature titanium alloy were studied. XRD results illustrated that the phase composition of the alloy after different heat treatments was mainly α phase and β phase. The microstructures showed that with the increase of the solution temperature, the content of the primary α phase gradually reduced, the β transformation structure increased by degrees, then, the number and size of secondary α phase increased obviously. The tensile results at room temperature (RT) illustrated that as the solution temperature increased, the strength of the alloy gradually increased, and the plasticity decreased slightly. The results of tensile test at 650 °C illustrated that the strength of the alloy enhanced with the increase of solution temperature, the plasticity decreased first and then increased, when the solution temperature increased to 1000 °C, the alloy had the best comprehensive mechanical properties, the tensile strength reached 714.01 MPa and the elongation was 8.48 %. Based on the room temperature and high temperature properties of the alloy, the best heat treatment process is finally determined as: 1000 °C/1 h/AC+650 °C/6 h/AC.


2012 ◽  
Vol 710 ◽  
pp. 119-124 ◽  
Author(s):  
Niraj Nayan ◽  
S.V.S. Narayana Murty ◽  
S.C. Sharma ◽  
K. Sreekumar ◽  
P.P. Sinha

The objective of the present study was to melt and cast AA2195 alloy in Vacuum Induction Melting (VIM) under dynamic inert atmosphere. These billets were homogenized and subsequently hot forged and rolled to sheets. The products in the form of sheets were subjected to T8 (Solution Treatment +WQ+CW+Aging) temper condition. Mechanical properties were evaluated at room temperature and correlated with microstructure. Highest mechanical properties obtained in T87 temper have been reported.


1993 ◽  
Vol 322 ◽  
Author(s):  
R. Suryanarayanan ◽  
S. M. L. Sastry ◽  
K. L. Jerina

AbstractSubstantial improvements have been reported in high temperature strength and creep resistance, and room temperature fracture toughness of molybdenum disilicide (MoSi2) reinforced with ductile or brittle reinforcements. The influence of Hot Isostatic Pressing (HIP) process parameters on the mechanical properties of MoSi2 based alloys was studied. Monolithic MoSi2 powder and MoSi2 powder blended with either niobium powder or silicon carbide whisker reinforcements were consolidated by HIP at 1200 − 1400°C, 207 MPa, and 1 - 4 hrs. The HIP'ed compacts were characterized for compression strength and creep resistance at 1100-1300°C. Fracture toughness was measured on single edge notched rectangular specimens at room temperature. Mechanical properties were correlated with post-HIP microstructural features.


1994 ◽  
Vol 364 ◽  
Author(s):  
B. P. Bewlay ◽  
M. R. Jackson ◽  
W. J. Reeder ◽  
H. A. Lipsitt

AbstractIn-situ composites based on binary Nb-Si alloys and consisting of a Nb solid solution with Nb3Si or Nb5Si3 have shown a promising combination of low temperature and high temperature mechanical properties. The environmental resistance and room temperature fracture toughness of these composites can be further enhanced by additions such as Ti, Hf, Cr, and Al. In the present study, ternary Nb-Ti-Si alloys were prepared by directional solidification to generate aligned two and three phase composites containing a Nb solid solution with Nb3Si and/or Nb5Si3. The present paper will describe microstructures, phase equilibria and fracture toughness of these composites. The improvement in the room temperature fracture toughness over binary Nb-Nb5Si3 composites is discussed.


2012 ◽  
Vol 710 ◽  
pp. 125-131 ◽  
Author(s):  
Niraj Nayan ◽  
S.V.S. Narayana Murty ◽  
S.C. Sharma ◽  
K. Sreekumar ◽  
Parameshwar Prasad Sinha

A novel technique of pure Lithium addition has been adopted for the processing of Al-Cu-Li alloy AA2195 cast ingots (7-8 kg each) in VIM under dynamic inert atmosphere, which gives more than 95% recovery of Lithium. The cast billets were homogenized, forged and converted into 12mm diameter rods by caliber rolling in the temperature range of 250°C, 300°C, 350°C and 400°C. The caliber rolled rods were treated to T8 (Solution Treatment+WQ+CW+Aging) condition. Mechanical properties were evaluated for T8 tempered bars at room temperature and correlated with microstructural observations. Highest mechanical properties in T87 temper have been obtained for rods caliber rolled at 350°C temperature.


2004 ◽  
Vol 449-452 ◽  
pp. 697-700
Author(s):  
Hai Bo Yang ◽  
Wei Li ◽  
Ai Dang Shan ◽  
Jian Sheng Wu

The microstructures and mechanical properties of arc-melting processed Mo3Si-Mo5Si3 eutectic have been investigated. The Vickers hardness of Mo3Si-Mo5Si3 eutectic alloy at room temperature is on the order of 1350Hv. The fracture toughness value of the alloy at room temperature is 1.39MPam1/2 measured by Single edge-notched beam specimen technique and 1.61MPam1/2 measured by Indentation technique. The compressive strengths at 1300 oC and 1400 oC under a strain rate of 10-4s-1 are about 550MPa and 300MPa respectively.


2016 ◽  
Vol 849 ◽  
pp. 603-608 ◽  
Author(s):  
Mei Ling Wu ◽  
Feng Wei Guo ◽  
Ming Li ◽  
Ya Fang Han

The effect of strontium (Sr) addition (0.2 at.%) on the microstructure and mechanical properties of Nb-12Si-22Ti alloys were studied. Microstructure of the alloys was observed by scanning electron microscope, and their phase compositions were analyzed with X-ray diffraction and Electro-Probe Microanalyzer. The room temperature fracture toughness was measured. The results indicated that the phases of Nbss and Nb3Si were presented in Nb-12Si-22Ti alloys. However, with the Al and Sr addition, the alloys were composed of Nbss and β-Nb5Si3. Compared with the Nb-12Si-22Ti alloys, the value of room temperature fracture toughness increased about 46% and 73% with the addition of Al and Sr alloy, respectively. The relationship between the microstructure and the mechanical properties was discussed.


2006 ◽  
Vol 306-308 ◽  
pp. 941-946
Author(s):  
Sheng Wu Wang ◽  
Tatsuo Tabaru ◽  
Hisatoshi Hirai ◽  
Hideto Ueno

Nb-base in-situ composites with the base composition of Nb-18Si-2HfC were prepared by conventional arc-melting. Their microstructures and mechanical properties, such as high-temperature strength and room temperature fracture toughness, were investigated to elucidate the effects of Re alloying. The in-situ composites predominantly have eutectic microstructures consisting of an Nb solid solution (NbSS) and Nb5Si3. The compressive strength increased with the increasing Re contents at 1470K and not at 1670 K. The strengthening effect observed at 1470 K is higher than that by W and Mo. Re alloying of about 2 % is valuable for improving both the high temperature strength and room temperature fracture toughness of Nb-18Si-2HfC base materials.


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