Mechanical properties of newly developed PM-alloys

Heavy duty applications of the automotive industry are forcing the PM' industry more and more to develop new high-strength materials. Herefore, two newly developed materials Fe8.0%Ni-1.O%Mo-0.5%C, as sintered, and Fe-1.5%Mo-0.5%C, as-sintered and quenched and tempered were investigated. The high fatigue performance of the first material obtained directly after sintering could be reached only by the second one after a heat treatment

Development of sintered con-rods for automotive engines

Within an international research program con-rods from the alloy Fe-1.5-Cu-0.6C, quenched and tempered, with densities mostly over 7.0 g/ccm in the highly stressed areas were developed and pressed in the single sintering technique. The PM' tooling for the compaction-sinter-size route was manufactured after extensive FEM and experimental stress analyses. After successful fatigue testing, the con-rods achieved final engine testing without any failures. The duration corresponded to 150.000 to 300.000 km normal european operational service

NANOG priming before full reprogramming may generate germ cell tumours

Reprogramming somatic cells into a pluripotent state brings patient-tailored, ethical controversy-free cellular therapy closer to reality. However, stem cells and cancer cells share many common characteristics; therefore, it is crucial to be able to discriminate between them. We generated two induced pluripotent stem cell (iPSC) lines, with NANOG pre-transduction followed by OCT3/4, SOX2, and LIN28 overexpression. One of the cell lines, CHiPS W, showed normal pluripotent stem cell characteristics, while the other, CHiPS A, though expressing pluripotency markers, failed to differentiate and gave rise to germ cell-like tumours in vivo. Comparative genomic hybridisation analysis of the generated iPS lines revealed that they were genetically more stable than human embryonic stem cell counterparts. This analysis proved to be predictive for the differentiation potential of analysed cells. Moreover, the CHiPS A line expressed a lower ratio of p53/p21 when compared to CHiPS W. NANOG pre-induction followed by OCT3/4, SOX2, MYC, and KLF4 induction resulted in the same tumour-inducing phenotype. These results underline the importance of a re-examination of the role of NANOG during reprogramming. Moreover, this reprogramming method may provide insights into primordial cell tumour formation and cancer stem cell transformation

The role of oxygen transfer in sintering of low alloy steel powder compacts: a review of the "internal getter" effect

The chemical aspects of sintering have to be considered, in particular the role of oxygen. For sintered alloy steels used for highly stressed components, traditional alloy elements have been Cu, Ni and Mo, which in their oxygen affinity are very similar to the base constituent iron. Advanced alloying systems however contain Cr, Mn and/or Si. In the present study it is shown that one of the principal aspects of sintering to be considered is oxygen transfer from the base iron oxides to the alloy elements, which then form oxides that are more difficult to reduce. This process, defined as “internal gettering”, occurs both in mixed powder compacts and in prealloyed materials, although through different mechanisms. The effect can at least be alleviated by presintering in H2 in the 400°C range, part of the oxygen being removed as H2O before internal gettering becomes kinetically effective. However, in industrial practice, this collides with delubricaton. Furthermore for both alloy variants high temperature sintering is advantageous because it enhances reduction of the more stable oxides, thus eliminating the effects of internal gettering.European Union Marie Sklodowska-Curie scholarshi