IMPROVEMENT OF AMBIENT DUCTILITY AND TOUGHNESS BY Γ PHASE PRECIPITATION IN NIAL-CR(MO)/NB ALLOYS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2898-2903 ◽  
Author(s):  
LINZHI TANG ◽  
SHUSUO LI ◽  
SHENGKAI GONG

Effects of different ratios of Ni to Al on the ductility and toughness of Ni 33+ x Al 28- x Cr 30 Mo 4 Nb 5 ( x =0, 6, 9, 12) alloys are investigated. High temperature compression test is also conducted. The results show that with ratio of Ni to Al up to 1.77, γ phase precipitation result in ductility and fracture toughness enhanced at room temperature. The reinforced Cr 2 Nb -type phase and γ phase benefit for the high temperature strength and room temperature ductility, respectively.

1985 ◽  
Vol 58 ◽  
Author(s):  
A. Brown ◽  
D. Raybould

ABSTRACTIn recent years, interest in high temperature aluminum alloys has increased. However, nearly all the data available is for simple extrusions. This paper looks at the properties of sheet made from a rapidly solidified Al-10Fe-2.5V-2Si alloy. The sheet is made by direct forging followed by hot rolling, this is readily scalable, so allowing the production of large sheet. The room temperature strength and fracture toughness of the sheet are comparable to those of 2014-T6. The high temperature strength, specific stiffness and corrosion resistance are excellent. Recently, improved thermomechanical processing and new alloys have allowed higher strengths and fracture toughness values to be obtained.


1990 ◽  
Vol 186 ◽  
Author(s):  
S. M. Russell ◽  
C. C Law ◽  
L. S. Lin ◽  
G. W. Levan

AbstractCobalt-modified NiAl alloys are being studied for their potential for room temperature ductility and toughness. An alloy of Ni - 29.3 a/o Al - 36.7 a/o Co has shown improved toughness and ductility with respect to binary NiAl alloys due in part to a stress-induced martensitic transformation. Furthermore, the cobalt additions have altered the slip behavior to {110}<111> type from {110} <001> for binary NiAl alloys. Hafnium was added to improve the alloy's relatively poor creep resistance and high temperature strength. Hf was found to be insoluble in the NiAlCo alloy and formed precipitates with a hexagonal structure. The Hfmodified alloy had improved high temperature strength. In addition, the Hf apparently changed the creep mechanism resulting in poorer creep resistance at low temperatures, but improved creep resistance at higher stresses and temperatures.


2010 ◽  
Vol 105-106 ◽  
pp. 218-221 ◽  
Author(s):  
Xuan Liu ◽  
Qiang Xu ◽  
Shi Zhen Zhu

ZrB2-SiC-B4C is sintered at 1700°C by spark plasma sintering process. The effect of B4C content on the mechanical properties and microstructure of ZrB2-SiC based ceramics is studied. The results show that, with the content of B4C increases, the relative density and room-temperature strength decrease in the ZrB2-SiC-B4C composite. The fracture toughness rises at first and then falls down. The high temperature strength increases.


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.


1996 ◽  
Vol 460 ◽  
Author(s):  
Toshihiro Hanamura ◽  
Keizo Hashimoto

ABSTRACTFor improving the room temperature tensile ductility of direct-cast gamma TiAl sheets without affecting their high-temperature strength, direct sheet casting with T1B2 particle dispersion is employed and conducted. The T1B2 addition and rapid cooling results in the formation of a fine equiaxed grain microstructure with an average grain size of ∼10μm, contributing to the increase in the room temperature ductility to 2.1% with the high-temperature tensile strength kept at about 200MPa. This improvement of room-temperature ductility is attributable to the following fact. The high oxygen content of this material, about 2500wt. ppm, is not harmful to the tensile ductility when the oxygen is in the solid solution of the 0:2 lamellar phase or in oxide particles, which are fine enough not to cause brittleness to the matrix. From these findings, a principle is proposed that oxygen is not harmful to the ductility of gamma TiAl when its microstructure containing oxygen is fine enough.


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