Fine structure of steel 5Kh3V3MFS after LTMT and standard heat treatment

1979 ◽  
Vol 21 (4) ◽  
pp. 273-277
Author(s):  
E. S. Sevast'yanov ◽  
A. I. Strikelev ◽  
I. V. Rakhov
Keyword(s):  
Heat Treatment ◽  
Fine Structure ◽  
Standard Heat Treatment ◽  
Standard Heat

Microstructure Evolution and Stress Rupture Properties of DD6 Single Crystal Superalloy after Overheating

2017 ◽  
Vol 898 ◽  
pp. 517-522 ◽  
Author(s):  
Shi Zhong Liu ◽  
Zhen Xue Shi ◽  
M. Han ◽  
Jia Rong Li
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Rupture Life ◽  
Stress Rupture ◽  
Standard Heat Treatment ◽  
Stress Rupture Life ◽  
Matrix Channel ◽  
Standard Heat ◽  
Stress Rupture Properties ◽  
Rupture Properties

The second generation single crystal superalloy DD6 after standard heat treatment was respectively overheated at 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1320°C for 1h and air cooled. The effect of overheating on the microstructure and stress rupture properties at 980°C/250MPa of the alloy was investigated. The results showed that the size of γ′ phase was slightly increased overheating at 1100°C, 1150°C and 1200°C. The size of γ′ phase had a big increase and its size distribution was very uneven after overheating at 1250°C. The small part of γ′ phase has serrated γ′/γ phase surface as a result of un-completely solution and the irregular small γ′ phase was in the majority when overheated at 1300°C. While all the irregular small γ′ phase precipitated again after completely solution when overheated at 1320°C. There was no fine second γ′ phase in the γ matrix channel of the alloy after standard heat treatment and overheating at 1320°C. But the fine second γ′ phase precipitated in the γ matrix channel after overheating at every temperature of 1100 °C~1300°C. No obvious change of the stress rupture life was found after overheating at 1100°C, 1150°C, 1200°C and 1250°C. The stress rupture life considerably reduced after overheating at 1300°C, whereas slightly reduced after overheating at 1320°C. The appearance of the raft had almost no change after overheating at 1100°C. With increasing of overheating temperature from 1100°C to 1250°C, the length of raft became shorter and the width thickening. The γ phase formed the wavy raft after overheating at 1300°C and 1320°C and the thickness of latter was larger than that of the former. Finally, the relationship between the microstructural evolution and stress rupture properties of the alloy after overheating was discussed.

Long-Time Thermal Structural Stability Study on NiCr20TiAl Alloy

2011 ◽  
Vol 399-401 ◽  
pp. 71-75
Author(s):  
Qiu Ying Yu ◽  
Zhi Shen ◽  
Mai Cang Zhang ◽  
Guo Qing Jia ◽  
Xi Shan Xie
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Treatment Condition ◽  
Ostwald Ripening ◽  
Heat Treatment Condition ◽  
Stability Study ◽  
Standard Heat Treatment ◽  
Standard Heat ◽  
Long Time ◽  
Coarsening Kinetics

The coarsening kinetics of main strengthening phase γ′ and the growth behavior of grain boundary carbides have been investigated on NiCr20TiAl alloy aged at 550~750°C for 200~10,000h. The precipitates of NiCr20TiAl alloy at standard heat treatment condition are γ′, M7C3, M23C6 and MC. The coarsening of γ′ precipitates proceeds by Ostwald ripening controlled by volume diffusion in the alloy. Grain boundary carbides M23C6 and M7C3 increase with ageing times and temperatures. The morphologies of precipitates after long-time ageing almost remain the same as that at standard heat treatment condition except 750°C.

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