Yes, the 7075 aluminum alloy blocks can be welded, but the process can be difficult due to the high strength and hardness of the alloy. Specialized welding techniques and equipment are recommended. It’s also important to note that welding can significantly decrease the strength of the material, so proper heat treatment and post-weld stress relief should be considered in order to maintain the strength properties of the alloy. Additionally, it’s important to be aware that welding aluminum alloys can produce hydrogen gas which can cause porosity and crack in the weld, so proper preheat, interpass temperatures and post-weld heat treatment are necessary.