shows the comparison of microstructural and mechanical properties of 92.5W-6.4Ni-1.1Fe
alloy obtained in the study.
The W-Ni-Fe alloy sintered using microwaves has a smaller average tungsten grain size
and higher content of tungsten due to the shorter processing time, leading to less tungsten
dissolution into the matrix when compared to the conventionally sintered counterpart. These
factors lead to a higher bulk hardness and tensile strength in the microwave-sintered W-Ni-
Fe alloy. The lower microhardness of the matrix was attributed to less tungsten dissolution
into the matrix.
For conventional sintering, the ductility was reported to be adversely affected by high
values of tungsten content, contiguity, connectivity and dihedral angle. Contrary to conventional
sintering, the microwave-sintered W-Ni-Fe alloy displayed significant improvement in
ductility, in spite of the higher strength values observed.
It was also reported that X-ray diffraction of the microwave-sintered W-Ni-Fe alloy did
not reveal the presence of any intermetallic phases, but NiW and Fe7W6 intermetallic phases
were detected in conventionally sintered specimens. It was suggested by the researchers that
the presence of these brittle intermetallic phases led to a degradation in mechanical
properties of conventionally sintered W-Ni-Fe alloy [80].
4.3.7 Tin-Based Alloys (Electronic Solders)
Tin is a versatile metal which is used predominantly in solder alloys in the electrical and
electronic sector, accounting for 34 % of its annual global production. Tin is also used