The influence of scanning speed on the laser metal deposition OF Ti/TiC powders

Abstract

The paper describes experimental work performed on the laser metal deposition (LMD) of titanium carbide powders on a pure titanium substrate. The understanding the effect of LMD processing parameters is vital in controlling the properties of the final product fabricated from the LMD process. The objective of the study is to characterize the influence of the laser scanning speed of the metal deposition of titanium and titanium carbide powders on a pure titanium substrate. Microstructural results showed that the substrate is characterized by two-phase morphology; alpha and beta phases. The deposit zone microstructures showed that the grains are of continuous columnar in nature. The heat-affected zone region grain areas appear to decrease with increasing in scanning speed for different samples at different scanning speeds. The height of samples was observed to decrease with an increase in the scanning speed. The microhardness results showed that the hardness of the deposits is greater than the hardness of the substrate. Wear-resistance performance results showed that the coefficient of friction of the substrate is greater than the coefficient of friction of the deposit samples. Similarly, the wear volume loss of material of the substrate is higher than the deposits. The deposit contains titanium carbide and, as such, this powder has improved the wear resistance performance of the substrate. Keywords: titanium, lasers, metal deposition, scanning speed lanek opisuje eksperimentalno delo pri laserskem nana{anju (angl. LMD) prahu titanovega karbida na podlago iz~istega titana. Upo{tevanje u~inkov LMD procesnih parametrov je klju~no za kontrolo lastnosti kon~nega proizvoda, izdelanega z LMD postopkom. Namen {tudije je dolo~iti vpliv hitrosti skeniranja laserja na nana{anje prahu kovinskega titana in titanovega karbida na podlago iz~istega titana. Rezultati mikrostrukturne karakterizacije so pokazali, da je za podlago zna~ilna dvofazna morfologija; alfa-in beta faza. Mikrostruktura nane{ene plasti je pokazala, da so zrna obi~ajno stebraste strukture. Zrna v podro~ju toplotno vplivane cone se zmanj{ujejo z nara{~anjem hitrosti skeniranja, pri razli~nih vzorcih in razli~nih hitrostih skeniranja. Vi{ina vzorcev pri razli~nih hitrostih skeniranja, se je zmanj{evala z nara{~anjem hitrosti skeniranja. Rezultati mikrotrdote so pokazali, da je trdota nanosa ve~ja od trdote podlage. Obna{anje pri obrabi je pokazalo, da je koeficient trenja podlage ve~ji kot pa koeficient trenja nanosa. Izguba materiala zaradi obrabe je ve~ja pri podlagi kot pa pri nanosu. Nanos vsebuje titanov karbid, zato je ta prah pove~al obrabno odpornost podlage.