View attachment 39507
Let's go over these deficiencies point by point. I'll try to be brief:
1. Single crystal blades/vanes with EBPVD: Single crystal blade/vane design & fabrication has been established reliably. This is not an issue anymore. Work is ongoing on improving the composition of alloys used for the SCBs.
The issue is the Electron Beam Physical Vapour Deposition (EBPVD) process. This process is used to deposit ultra-thin layers of Thermal Barrier Coating (TBC) on blades & vanes. DMRL has mastered some other PVD & CVD processes. But EBPVD remains out of reach. The main advantage of EBPVD is that the TBC is coated with extreme uniformity. Other deposition processes don't go anywhere near these levels of uniformity in application. Thus, some spots on the blades/vanes end up receiving a lower than necessary thickness of TBC. Those spots become the initiation point of failure.
We currently get EBPVD machines from Germany. They are very expensive & incredible hard to acquire.
2. Powder metallurgy discs: We do have fabrication capacity of powder metallurgy discs. But our discs so far have had unacceptable levels of porosity to be used on a jet engine. DMRL will probably take 4-5 years to increase the specific gravity of these discs to the point where they can start testing them of engines.
We are currently facing a raw material supply problem for some of our powder metallurgy projects. No investments have been made into setting up domestic raw materials factories.
3. Blisk technologies: We have most of what we need to make Blisks of any size. The only limitation is the lack of large isothermal presses. Those are coming up:
4. Damage tolerant disc design: We cannot design damage tolerant disks until we have our own engine FOD test facility. This is an infra & investment issue. Not a capability issue.
5. Polymer Matrix Composite Bypass duct: So far, our expertise in fabricating polymer matrix composites is limited to the resin infusion processes. Resin infusion process produces very good quality composites for structural & surface applications. But the problem of using resin infusion process is that some amount of the resin remains stuck within the composite. This remanent slowly dries away naturally within year or so.
Now, bypass ducts aren't part of the "hot" section of the engine. But they do tend to get heated up. That sudden heat shock will cause the all the resin to burn/dry away all at once. That will change the shape of the duct.
We need to master a new process of making composites. A process that does not need resins. Can be done, will take some time though.
6. FADEC: We can make FADEC systems. But even if we design our own chips, they will be reliant on foreign fabricated chips for the sometime. ISRO's SCL after it upgrades to a 28 nm node can take over this role. Or maybe one of the upcoming civilian fabs. Again, this is an infra & investment issue. Not a capability issue.
7 & 8. Large Structural casings & CERMET Flaps: I need to read more about these before I comment.
