This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of

chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and

mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8

preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of

the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional

phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably

the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al)

solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests

have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength

Rp0.2 (about 21%) and to a small extent elongation A.

This paper presents the results of hypoeutectic 226 grade alloy as well as prepared on its basis Al-Si alloy containing Cr, V and Mo. The

additives tested were added as AlCr15, AlV10 and AlMo8 master alloys. Alloys tested were poured into DTA sampler as well as using

pressure die casting. An amount of Cr, V and Mo additives in alloy poured into DTA sampler comprised within the range approximately

0.05-0.35%. Alloys to pressure die casting contained 0.05-0.20% Cr, V and Mo. The crystallization process was examined using the derivative

thermal analysis (DTA). The microstructure of castings made in the DTA sampler as well as castings made with use of pressure die

casting were examined. The basic mechanical properties of castings made using pressure die casting were defined too. It has been shown

in the DTA curves of Al-Si alloy containing approximately 0.30 and 0.35% Cr, Mo, and V there is an additional thermal effect probably

caused by a peritectic crystallization of intermetallic phases containing the aforementioned additives. These phases have a morphology

similar to the walled and a relatively large size. The analogous phases also occur in pressure die casting alloys containing 0.10% or more

additions of Cr, V and Mo. The appearance of these phases in pressure die casting Al-Si alloys coincides with a decrease in the value of

the tensile strength Rm and the elongation A. It has been shown die castings made of Al-Si alloys containing the aforementioned additives

have a higher Rm and A than 226 alloy.