We usually use XRD to evaluate the effect of mechanical activation(high energy milling, MA for short). After MA, some line broadening and reduction in height of the diffraction peaks occurred, some peaks would become invisible.
Somebody claimed that the disappeared peak means the selective rupture of lattice through this plane, while someone said the microstrain only affected high angle peaks and there was no "selective rupture", this phenomenon may be just due to the decrease of peak intensity. If the peak was weak before MA, after MA it would be lower and invisible.
Please tell me which one is true, thank you!
Dear Song Zhao, The height of the peaks indicates the amount of planes in the crystallographic plane of the respective phases. the width of the peak indicates what the structure is small or large. If the study site is very wide, it has a large structure. At a narrow peak, the structure is small. The lower peaks indicate the presence of small oriented crystallographic planes. With respect Emil Yankov
Dear Song,
Peak depends upon relative density and energy of absorption. Generally, the mechanical behavior of the lattice structure material can be defined by quasi-static and dynamic testing; lattice structures with high relative densities are stretch-dominated, whereas those with low relative densities are bending-dominated. After MA, under dynamic load, relative densities are minimized by the influence of the lattice topology on the deformation process plot. Hence peaks are narrow and deviations occur in peak broadening level. During the separation process, the structure of metal/ material can sustain damage, such as regional overlapping or rupture. The dimensions of the produced lattice struts may differ from those of the designed struts. These deviations is due to the orientation in relation to the specimen-building direction.
Ashish
Emil Hristov Yankov ,thank you.
I know the meaning of height and width, I mean, after a long time high energy milling, the grain size and microstructure changed. These two effects cause the broadening of peaks and a consequent decrease in peak heights.
For a strong peak, the change is obvious, while for a weak peak, the little decrease in peak height would make it almost invisible. I think this may suggest the disappearance of the peak, in other words, the selective rupture of lattice through this plane.
Also, with long time milling, some nearby peaks would be so overlapping that I'd rather fit them as one.
Does that make sense?
Ashish Thakur, thank you, the "overlapping and rupture" is the key.
I was told that the rupture only occurs in the high angle, and it is more common in rare earth.
I'm studying on chalcopyrite, does the selective rapture exist in it?
If so, could the rapture take place at a normal angle (like 2θ=40) alone? I mean a peak disappeared by rapture and its nearby peak broadened, because some nearby peaks were so overlapping that I'd rather fit them as one.
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