Cov khoom siv roj hmab, cov khoom siv txhaj tshuaj, thiab cov khoom siv zinc-magnesium-aluminium alloy yuav tawv thiab tawg thaum qhov kub txo qis, thiab lawv yuav poob lawv qhov elasticity. Qhov tseem ceeb, thaum qis dua qhov kub ntawm cov khoom siv, txawm tias siv zog tsawg tsawg los ua rau cov khoom no tawg. Thaum kub qis, lub teeb ci (cov khoom ntau dhau nyob ib puag ncig cov khoom) yuav tawg sai dua li cov khoom nws tus kheej. Thaum lub sijhawm tseem ceeb uas lub teeb ci tau tawg tab sis cov khoom tseem khaws nws qhov elasticity, kev txau cov yas pellets uas tsim tshwj xeeb yog siv los cuam tshuam cov khoom. Cov txheej txheem no tshem tawm lub teeb ci yam tsis muaj kev cuam tshuam rau kev ncaj ncees lossis qhov zoo ntawm cov khoom.