On the Nature of Cell Boundaries in Rapidly Cast Al-Alloys

The impurity cell structure of rapidly cast Al-Si, Al-Mg and Al-Ag alloys is investigated with respect to the occurrence of second phase and dislocations as a function of solute concentration. Considering the dislocation arrangement, three types of cell boundaries corresponding to various concentration ranges could be distinguished. Comparison of the three alloys leads to the conclusion that the dislocations are introduced by constitutional stresses, which depend only on the severity of segregation and the difference in atomic size between solvent and solute atoms

Enhanced densification of white cast iron powders by cyclic phase transformations under stress

It is shown that densification of white cast iron powders under stress can be enhanced by multiple phase transformations through thermal cycling. This enhancement occurs by accelerated creep flow during phase changes (transformation superplasticity). The approximate stress range where transformation-assisted densification can occur is shown to be between 1.7 MPa (250 psi) and 34.5 MPa (5000 psi). Below 1.7 MPa insufficient strain occurs during phase transformation to cause significant densification even after many transformation cycles. Above 34.5 MPa, densification occurs principally by normal slip creep. Transformation warm pressing of white cast iron powders leads to dense compacts at low pressures and short times. In addition, because the transformation temperature is low, the ultrafine structures existing in the original powders are retained in the densified compacts.Peer reviewe

A flow cytometric method to detect apoptosis-related protein expression in minimal residual disease in acute myeloid leukemia.

0.0001). Secondly, the influence of the permeabilization procedure on LAP expression was investigated in 38 AML samples at diagnosis and in 42 MRD samples. Quantification of the frequency of LAP+ cells with and without permeabilization showed no significant differences (diagnosis: P= 0.57, follow-up: P= 0.43). The flow cytometric protocol thus enables analysis of apoptosis-related proteins at different stages of the disease, which will lead to a better understanding of the role of apoptosis resistance in the emergence of MRD in AML