Effect of 12 Heat Treatment Conditions After HIP Process on Microstructural Refurbishment in Cast Nickel-Based Superalloy, GTD-111

A Case Study on Ni based Super Alloys Ageing for Improvement of its Properties

“…Typically, higher cooling rates allow an increase in mechanical properties, but are often accompanied by an increase in unacceptable component internal residual stresses. Wangyao et al [3] have provided the new method of repairing the super alloy and the reestablishment of the initial properties and near original microstructure of the long term used or damaged parts for the economic reasons. The alloys standard heat treatment not effective when applied long-term serviced microstructure to reestablishment of mechanical properties.…”

Effect of Reheat Treatment on Microstructural Refurbishment and Hardness of the As-cast Inconel 738

“…Then, the microstructure after long-term service could be fully restored after aging. However, the applied higher solutionizing temperature conditions provide lower area fraction of γ ′ phase, comparing with the standard reheat treatment condition [28,31,32].…”

“…This condition could induce microstructural degradation of turbine blade, resulting in lower mechanical properties and service life time. Because mechanical properties of turbine blade are strongly related to the microstructures, many previous research works [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] have been carried out to investigate the relationship between microstructure and mechanical properties. The microstructural degradation mainly involves coarsening or rafting of γ ′ precipitated particles, resulting in lower volume or area fraction of γ ′ particle as well as lower effect of strengthening mechanism for the material.…”

“…There are many research works [10][11][13][14][15][16][17][18][19][20][21][22][23][24][25] investigating the effect of reheat treatment conditions on the obtained microstructure in cast nickel-based superalloys of various grades, including works [1,[21][22][23][24][25][26][27][28][29][30][31][32] on Inconel 738. The previous studies [1] indicated that the proper reheat treatment procedure should include solutionizing Inconel 738 in the temperature range of 1,398-1,478 K for 7.2-21.6 ks followed by a rapid gas quench (25 K to 55 K/min.…”

Microstructural evolution in damaged IN738LC alloy during various steps of rejuvenation heat treatments

“…The influence of rejuvenation heat treatments on recovery of mechanical properties in damaged nickel base superalloys has been studied by numerous authors. They correlated the observed recovery to microstructural restoration (through re-solution and re-precipitation), sintering of cavities (by vacancy diffusion under the action of surface tension and/or supplied pressure), inhibition of growth in grain boundary cavities (via isolating them within the grain interiors through recrystallization or grain growth), and changes in dislocations structure [11][12][13][14][15][16][17][18][19][20].…”