Hlau yog suav tias yog cov hlau zoo tshaj plaws los siv thaum ua cov hlau txuas vim nws cov khoom siv kho tshuab.
Hardness:Lub peev xwm zam qhov deg indentation (localized yas deformation) thiab khawb yog hu ua hardness. Hardness tuaj yeem qhia txog kev khawb tsis kam, puas ua haujlwm, indentation kuj, thiab txawm tias shaping lossis localized yas deformation kuj; yog li ntawd, nws yog kab tias cov khoom siv tsis zoo tshaj plaws. Los ntawm ib qho engineering nam, hardness yog qhov tseem ceeb vim hais tias nws ua rau kom tsis kam hnav los ntawm kev sib txhuam los yog yaig los ntawm chav, roj, thiab dej.
Toughness:Muaj peev xwm nqus tau lub zog tsis muaj kev tawg lossis tawg. Toughness kuj yog lub peev xwm ntawm ib yam khoom los tiv thaiv tawg thaum strained. Qhov txawv ntawm toughness thiab hardness yog tias cov khoom uas deforms ntau yam tsis muaj kev tawg tuaj yeem hu ua tawv heev tab sis tsis tawv.
