Considering the diffusion welding of the following material combinations, how easy would it be to produce welds in each case? Explain your answer in each case. a. Pure aluminum (AA1100) to aluminum alloy AA6061
b. Ti–6Al–4V to Ti–6Al–6V–2Sn
c. Ni-base Alloy 625 to Alloy 625
d. AISI 304 austenitic stainless steel to AISI 304.

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?

The sum of the normal stresses does not change as the stress state rotates through an angle. a)-trune b)- false

On solidification from a melt, the polymer polyethylene forms a semi-crystalline spherulite structure. (i) sketch an individual spherulite and label the amorphous and crystalline regions. (ii) draw a schematic to show the changes in specific volume with temperature during cooling from the melt, comparing it to the theoretical extremes of fully crystalline and fully amorphous (indicate tm and tg)