Thermal Cycling

During thermal cycling, solder undergoes progressive inelastic deformations at the grain-boundary.  As the change in temperature increases, so does the amount of damage done.  Alpha’s solder material is comprised of optimal silver and tin content, as well as single crystal microstructures, to increase thermal cycling reliability.

Due to their composition, some alloys will exhibit better thermal fatigue resistance under more difficult thermal cycling conditions than others. It is well established in the circuit board assembly industry that Pb-free alloys with higher amounts of silver (Ag) withstand harsher test conditions than lower or no Ag bearing alloys.Alpha has engineered a series of Pb-free alloys with the end use environment of the final product in mind.

Bar Solder Alloys

Use the chart below to determine which Alpha alloy is right for you. Simply align the type of assembly being made with the appropriate alloy.

 Assembly Type
Simple, single sided, FR2 / CEM-1 laminates
Dual sided FR-4 w/ PTH's, 1.6mm thick, up to 4 inner copper layers, metallized pad finishes
Complex, up to 12 inner copper layers, OSP pad finishes, all processing in air
>2.4mm thick, >12 inner copper layers, large high heat capacity components
 SACX Plus 0807

 SAC alloys label for table
  1%+ flux solids, L0, pin testable
Flux Type
  SACX Plus 0307
    4%+ flux solids, L or M0, pin testable
SnCX Plus™ 07
          4%+ flux solids, L or M0, moderately pin testable
            7%+ flux solids, L,M or H1, not pin testable
0ºC to 100ºC - standard profile cycles
0ºC to 100ºC - standard and shock profile cycles
- 25ºC to 125ºC - standard and shock profile cycles
- 45ºC to 125ºC - standard and shock profile cycles
Thermal Fatigue Resistance



High Thermo-Mechanical Fatigue and Drop Shock Resistant Alloys for Ball-Grid Array Package Applications - Download Whitepaper


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