The first took place on the westbound carriageway between Junction 3 and 4 at Telford, at around 2am.
The second happened at around 5am, also between Junction 3 and 4.
In the first incident a lorry and trailer had overheated brakes causing the tyres to explode.
Three fire crews attended and used hoses to reduce the heat of the brakes.
The second incident involved another lorry with brakes on fire.
The hard shoulder and one lane were closed while fire crews used jets to extinguish the fire.
The Highways Agency also attended both incidents.
During the second incident the fire service also pleaded for drivers on the road to slow down, with the crews working in the road.
Craig Jackson, station manager from Shrewsbury said: "Please slow down. Vehicles are still passing quickly in foggy conditions with lane restrictions in place. Crews are working on carriageway."