A handy clip of when Vibranium meets Uru:
It probably wouldn't have mattered how hard Thor tried to hit, the only difference would have been the size of the shockwave.
Regarding the limits of vibranium, from the Wiki:
Despite its near-indestructible nature, vibranium's durability ultimately has its limits. The energy projected by the Infinity Stone in Vision's forehead combined with Iron Man's repulsors and a lightning bolt from Mjølnir was able to slowly melt away Ultron's vibranium outer shell, while Vision's vibranium body was later disintegrated by Scarlet Witch's full-power energy bolt. Scarlet Witch was also able to break through the metal with her telekinesis. It is also shown that Corvus Glaive's glaive could easily pierce through Vision’s vibranium body, thus preventing him from phasing. Thanos' Double-Edged Sword was able to shatter vibranium with several hits. It is also revealed that vibranium is vulnerable and rendered defunct by sonic-based equipment such as Ulysses Klaue's Prosthetic Arm and the sonic stabilizers that are built on tracks of the Wakandan Maglev Train within the Great Mound. Vibranium is also highly unstable when transported at high speed. Additionally, sufficiently high levels of strength can overcome through its durability, as the immensely strong Thanos was able to break Vision's forehead to acquire the Mind Stone and shatter Captain America's Shield.
- Mjolnir was shattered by Hela. While offscreen Doctor Strange could have done the reverse-time trick and repaired it there's no indication he did.
- Stormbreaker is in the hands of Thor who was last seen gallivanting around the galaxy with the Guardians.
- Scarlet Witch is currently hiding some place remote and isn't exactly reachable
- Thanos had destroyed the infinity stones, and Thanos himself and his minions and gear were all turned to dust by Iron Man's sacrifice
