Microstructure and Mechanical Properties of the Wide-Gap Region Brazed with Various Powder Mixing Ratios of Additive to Filler Metal Powders

2006 ◽  
Vol 118 ◽  
pp. 479-484 ◽  
Author(s):  
Yong Hwan Kim ◽  
S.I. Kwun

This study investigated the microstructure and mechanical properties of the wide-gap region brazed with various powder mixing ratios of additive powder (IN738) to filler metal powder (DF4B). The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr at 1230°C for 1 hr. The microstructure of the brazed region was analyzed by FESEM and AES. The wide-gap region brazed with 60wt.% IN738 additive powder and 40 wt.% DF 4B filler metal powder had a microstructure consisting of Ni solid solution + γ' and (Cr, W)2B. The fracture strength of the wide-gap region brazed with 60 wt.% IN738 additive and 40 wt.% DF 4B powder was as high as 832 MPa at room temperature. It was found that the (Cr, W)2B and pores in the brazed region are important microstructural factors affecting the mechanical properties of the wide-gap brazed region.

2007 ◽  
Vol 345-346 ◽  
pp. 1449-1452 ◽  
Author(s):  
Yong Hwan Kim ◽  
Il Ho Kim ◽  
K.T. Kim ◽  
Seung Y. Shin

The microstructure and bonding strength of the wide-gap region brazed with different filler metal powder (BNi-3 and DF 4B) and various powder mixing ratios of additive powder to filler metal powder were investigated. The microstructure characterization showed that Cr borides with a blocky morphology were existed in the brazed region in both filler metal powder. The bonding strength of the wide-gap region brazed with 60 wt.% IN738 additive and 40 wt.% DF 4B powder exhibited 92% tensile strength of IN738 superalloy at room temperature. The Cracks in the wide-gap brazed region initiated at the intermetallic compound and eutectic structure, and then propagated through them.


2006 ◽  
Vol 306-308 ◽  
pp. 935-940 ◽  
Author(s):  
Yong Hwan Kim ◽  
Ki Tae Kim ◽  
Il Ho Kim

This study investigated the microstructure and mechanical properties of a wide-gap region brazed with various powders mixing ratios of additive powder to filler metal powder. The IN738 and BNi-3 alloy powders were used as additive and filler metal powder for the brazing process. The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr. It was observed that the region brazed with only filler metal had a microstructure consisting of fully eutectic and dendrite structures. However, the region brazed with 60wt.% IN738 additive powder consisted of IN738 additive, Ni3B-Ni eutectic and (Cr, W)B. The fracture strength of the wide-gap region (70 wt.% additive and 30 wt.% filler metal powder) was as high as 687 MPa at room temperature. The Cracks in the wide-gap brazed region initiated at the Ni3B-Ni eutectic and (Cr, W)B, and then propagated through them. It was found that the Ni3B-Ni eutectic and (Cr, W)B in the brazed region are important microstructural factors affecting the mechanical properties of the wide-gap brazed region.


2005 ◽  
Vol 297-300 ◽  
pp. 2876-2882 ◽  
Author(s):  
Yong Hwan Kim ◽  
Il Ho Kim ◽  
C.S. Kim

This study investigated the microstructure and mechanical properties of a wide-gap region brazed with various process variables. The IN738 and DF 4B alloy powders were used as additive and filler metal powder for the brazing process. The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr. The wide-gap region brazed with 60wt.% IN738 additive powder had a microstructure consisting of IN738 additive and (Cr, W)2B. The fracture strength of the wide-gap region (60 wt.% additive and 40 wt.% filler metal powder) brazed at 1230°C for 30hr was as high as 862MPa (93% of base material strength). It was observed that the brazing temperature was the main process variable affecting the mechanical properties of the wide-gap brazed region. The creep rupture life of the region brazed with 60wt.% additive and 40 wt.% was longer than that of other brazed samples. The Cracks in the wide-gap brazed region initiated at the (Cr, W)2B and propagated through them. It was found that the (Cr, W)2B and the pore in the brazed region are important microstructural factors affecting the mechanical properties of the wide-gap brazed region.


2005 ◽  
Vol 486-487 ◽  
pp. 113-116
Author(s):  
Yong Hwan Kim ◽  
S.I. Kwun

The microstructural changes and the relations between mechanical properties and additive powder with various brazing temperatures and times were investigated. The IN738 and BNi-3 alloy powders were used as an additive and filler metal powders for the brazing process. The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr. The wide-gap region brazed with 60wt.% IN738 additive powder had a microstructure consisting of IN738 additive, and binary eutectic of Ni3B-Ni, and (Cr, W)B. As the brazing temperature and time were increased, the size of IN738 additive powder increased to 181µm, which decreased the amount of low strength Ni3B-Ni eutectic structure, thereby increasing the fracture strength of the wide-gap brazed region. Cracks in the brazed region were observed to propagate through the Ni3B-Ni structure, which lowered the fracture strength of the wide-gap brazed region.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 875
Author(s):  
Hao Tian ◽  
Jianchao He ◽  
Jinbao Hou ◽  
Yanlong Lv

TiB crystal whiskers (TiBw) can be synthesized in situ in Ti alloy matrix through powder metallurgy for the preparation of a new type of ceramic fiber-reinforced Ti matrix composite (TMC) TiBw/Ti-6Al-4V. In the TiBw/Ti-6Al-4V TMC, the reinforced phase/matrix interface is clean and has superior comprehensive mechanical properties, but its machinability is degraded. Hence, the bonding of reliable materials is important. To further optimize the TiBw/Ti-6Al-4V brazing technology and determine the relationship between the microstructure and tensile property of the brazed joint, results demonstrate that the elements of brazing filler metal are under sufficient and uniform diffusion, the microstructure is the typical Widmanstätten structure, and fine granular compounds in β phase are observed. The average tensile strength of the brazing specimen is 998 MPa under room temperature, which is 97.3% of that of the base metal. During the high-temperature (400 °C) tensile process, a fracture occurred at the base metal of the highest tensile test specimen with strength reaching 689 MPa, and the tensile fracture involved a combination of intergranular and transgranular modes at both room temperature and 400 °C. The fracture surface has dimples, secondary cracks are generated by the fracture of TiB whiskers, and large holes form when whole TiB whiskers are removed. The proposed algorithm provides evidence for promoting the application of TiBw/Ti-6Al-4V TMCs in practical production.


2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.


Sign in / Sign up

Export Citation Format

Share Document