After annealing the PdCu nanoparticle mixtures, they have different size distributions.
We also investigated the composition of the PdCu nanoparticle mixtures using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and energy dispersive X-ray spectroscopy (EDX).
The bulk PdCu phase diagram shown in Figure 2 reveals that PdCu alloys can take several crystalline structures and undergo solid-phase structural transformations that depend on temperature and composition .
This indicates that the two metals intermix forming PdCu nanoparticles with a predominantly B2 structure, similar to observations for other compositions [2, 3, 7, 12].
The PdCu B2 structure transforms into two different fcc alloy structures.
This structural evolution is unique and has not been observed previously either in PdCu 1 : 2 composition  or in PdCu 3 : 1 composition as will be discussed in the next section.
Wearout Reliability of Au and PdCu Ball Bonds in HAST and UHAST.
It also reveals higher cycles-to-failure for PdCu ball bonds compared to Au ball bonds.
Figure 2 indicates the wearout reliability Weibull plot comparing PdCu wire and Au wire.
However, PdCu wire exhibits slightly lower UHAST stress compared to conventional Au wire as shown in Figure 3.
Thermomechanical degree of Au and PdCu ball bonds was investigated through Temperature Cycling, (-40[degrees]C to 150[degrees]C condition TC).
A representative PdCu ball bond cross-section SEM image confirms CuAl interface fineline cracking as shown in Figure 7.