Crystallization model of magnesium primary phase in the AZ91/SiC composite

The work presents the results of the investigations of the effect of intensive cooling of alloy AZ91 with an addition of chromium on the microstructure and mechanical properties of the obtained casts. The experimental castings were made in ceramic moulds preliminarily heated to 180°C, into which alloy AZ91 with the addition was poured. Within the implementation of the research, a comparison was made of the microstructure and mechanical properties of the castings obtained in ceramic moulds cooled at room temperature and the ones intensively cooled in a cooling liquid. The kinetics and dynamics as well as the thermal effects recorded by the TDA method were compared. Metallographic tests were performed with the use of an optical microscope and the strength properties of the obtained castings were examined: UTS (Rm), elongation (A%), and HB hardness.

Section: Introductionmentioning

confidence: 99%

Effect of Intensive Cooling of Alloy AZ91 with a Chromium Addition on the Microstructure and Mechanical Properties of the Casting

Rapiejko

Pisarek

Pacyniak

2017

“…This means that the conditions for inclusion formation in the course of crystallization processes are favorable. The concentration C i0 of a given component "i" in the first part of the solidified phase is [17][18]: (18) where:…”

Section: Model Of Steel Components Segregation During Solidificationmentioning

confidence: 99%

“…Time needed for a layer to solidify, i.e. local solidification time t s , depends on the cooling rate P (K/min) [17][18]:…”

Section: Model Of Steel Components Segregation During Solidificationmentioning

confidence: 99%

Modeling of TiN and Ti2O3 Precipitates Formation During Solidification of Steel/ Modelowanie Powstawania Wydzieleń TiN I Ti2O3 W Procesie Krzepnięcia Stali

Kalisz¹,

Żak²

2014

Self Cite

The formation of titanium nitride precipitations during solidification of steel was modeled with own computer software based on Ueshima model. A thermodynamic parameters database was worked out on the basis of literature study. Calculations were performed for two types of steel; one of them was high in titanium. The quantity of produced titanium nitrogen inclusions was calculated. The authors analyzed changes in nitrogen, titanium and oxygen content in the course of segregation of steel components on the solidification front. The influence of solidification rate on the process of precipitation formation was analyzed.Keywords: titanium nitride, solidification of steel, segregation, computer simulation Praca zajmuje się modelowaniem powstawania wydzieleń azotku tytanu w stali podczas krzepnięcia. Zastosowano procedurę obliczeniową z wykorzystaniem modelu Ueshima przy pomocy własnego programu komputerowego. Na podstawie studiów literaturowych przygotowano bazę danych parametrów termodynamicznych. Obliczenia wykonano dla dwóch gatunków stali, z których jeden charakteryzował się wysoką zawartością tytanu. Obliczono ilość powstających wydzieleń azotku tytanu, przeanalizowano zmiany zawartości azotu, tytanu i tlenu w wyniku procesów segregacji składników w stali na froncie krzepnięcia. Zbadano wpływ szybkości krzepnięcia na proces powstawania wydzieleń.

“…It is favourable that strength, elongation as well as fracture toughness increase, similarly as after grain refinement through melt inoculation, which is commonly used in foundry practice of Al, Mg or Zn-based alloys, e.g. [1][2][3]. Materials crystallised under pressure have properties surpassing the same materials that are gravity cast and solidified in permanent casting moulds [5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Pressure on the Crystallisation of AlSi7Mg Alloy

Pastirčák

Ščury

2017

This paper deals with influencing the crystallisation of Al alloys by a direct squeeze casting method. The effects of changed cooling rates of the casting is evaluated using a heat transfer coefficient at different casting conditions. The experimental results obtained by temperature measurement of the casting and the mould were used to predict the casting and mould surface temperatures using regression curves. The measured temperatures in the sub-surface layers were used to determine the amount of heat transferred from the casting to the mould. The amount of transferred heat increased 20-fold due to the effect of pressure. We also evaluated the effect of the acting pressure on the mechanical properties and microstructure of the alloy used. The process parameters were varied in the experiment.